General Interest

417 posts

Thanks Brad!

Please give Brad Bender a hardy, and well deserved, “Thank you” the next several times you see him.  He has tirelessly monitored the restrictions placed upon our flying site.  He stayed in near constant communication with the Parks Dept. Rangers and the SD Police.  He got the field opened up, arranged for the field cleaning and repair, and most recently, even got the Porta Poti opened back up by instituting a strict cleaning regiment that the Rangers found acceptable.  (I personally thank him from the bottom of my bladder).  It is this kind of leadership that makes our club truly exceptional.  So please, say: “Thanks Brad!”, shower him with gifts, offer to fly his planes for him, stop peeing on his wheels, or whatever you need to do to show your appreciation.

Steve B.

Treasurer’s Report for June/July 2020

I’m very excited that we’re finally open for flying again! I went flying the last two weekends, and the field has been pretty quiet. Last Sunday, I had a nice little impromptu picnic at the field with Brad, Lisa, and Steve when Lisa brought some mouth watering chile relleno and pozole. I couldn’t have asked for a better Sunday!
We have 268 members as of June 23rd, and our finances are healthy. Even though we’re not able to raise funds for the holiday party this year, we had a generous donation by John Forester’s estate and AMA grant that fully funds our events for the remainder of the year. I look forward to seeing you all again soon as the county continues to re-open.
Stay Safe!
6S batteries were strategically placed to hold down the tablecloth when the wind picked up.

FAA – Recreational Flyer Registration Renewals

Twitter ButtonFacebook Button

Recreational Flyer Registration Renewals

The Federal Aviation Administration (FAA) has important registration information for drone recreational flyers whose registration was automatically extended until December 12, 2020.

Your registration expires in 180 days and you can now renew it in your FAADroneZone dashboard:

Drone Registration Dashboard

  • Once you click ‘renew’ the process is the same as when you initially registered.
  • Once you have renewed, to print an updated registration card: Login to the FAADroneZone, select the Recreational Flyer Dashboard and select Print.

How much does it cost to renew a registration?
$5 through the FAADroneZone.

Why Was My Registration Extended?
The National Defense Authorization Act for 2018 restored the FAA’s registration rule with respect to model aircraft and recreational flying. If you registered prior to December 12, 2017 and did not request to have your registration information deleted, the FAA extended the expiration date until December 12, 2020, which is three years from the rule restoration date. If you requested a refund of registration fees, you would have had to re-register again after December 12, 2017. Therefore, your expiration date would now also be December 12, 2020, or later. At this time you can retain your registration number.

Questions? Contact

SEFSD Founder Chuck Grim Has Passed

My Friend Chuck Grim

By Steve Manganelli

To most current members of SEFSD, Chuck was the guy in the cool red Tesla Model X. Few people know that Chuck is actually the founder of SEFSD! I don’t think Chuck flew in several years having battled cancer for most of the last 10; his health not sufficient to allow him to participate in our pastime. Chuck was always the quiet guy, tirelessly turning the cranks behind the scenes; never the loudmouth front man, always the selfless supporter. To me Chuck was both a friend and co-worker, we were both career Engineers at NAVAIR/North Island, him retiring about 2010 and myself in 2019.

Turning back the clock to about 1990, Chuck knew that Steve Neu and myself were experimenting with electric powered R/C models. Chuck suggested, “Why don’t you bring one to work and demonstrate it for us during lunch in the newly built park in Coronado”. Sounded like a plan to me, I brought a 7-cell racer I’d designed called the DC Tempest. That was (7) 1.2 Ah round cells, not 7S something or the other, more like 2S1200 but weighed more like 3S3300! With a crowd of other Engineers including Kurt Fowler, Lynn Heffern and of course Chuck eagerly looking on, the DC tempest was tossed and made that park seemed tiny. Talk about turn around maneuvers, that’s all I could do! Fortunately all of San Diego Bay was available to set up my landing approach nothing went wrong during a couple of minutes of loops and rolls; the Tempest settled into the grass without problems. The assembled crowd of Chuck’s fellow Engineers were suitably impressed. Chuck clearly thought there was a future in electric powered R/C.

Not too much later, I was hanging out in Chucks office when he said something like “Steve, this electric thing is clearly viable, what do you think about starting a new club in San Diego dedicated to electric propulsion?” “We would be strictly electric, no ICE would be allowed, and because we’re avowed to be quiet, finding a club field should be easy!” At that time, I was unaware that Chuck was dabbling in R/C modeling and was experimenting with E-power also. I said, “OK sounds like a plan”. We (probably he, because that was Chuck) ginned up a flyer announcing an introductory meeting, we set a date a few weeks in the future at some community center I don’t remember. We distributed these flyers to all the Hobby shops in town (there were 5 or 6 back then, sadly more than there are now). We were astonished that more than 30 people showed up and by the end of that meeting we agreed to form a club and collected $5 dues from each person present. Of course, as organizers of the group, myself and Chuck and probably Steve Neu were sitting at the head table pontificating over the assembled masses. When the dust cleared, Chuck managed to elect himself Treasurer or Secretary and myself as President! Pretty darn crafty for someone for which a club was his own idea! One topic of discussion is what we would name ourselves. “Prop Busters” or “Battery Burners” of San Diego certainly wouldn’t do. Chuck wanted us to have a more regal moniker. Chuck already had a name “Silent Electric Flyers of San Diego”, which was derived from Silent Electric Flyers of Long Island, an East Coast group whose exploits Chuck admired and I’m sure he hoped we’d eventually usurp.

Chuck, never the hero observed Steve Neu and others flying FAI-F5B and managed to get himself “appointed” as Team Manager for at least (3) bi-annual World Championship Teams. The Team Manager is the person whom gets to use his spare time, “spare” vacation time and money to organize a trip to Europe carrying huge model boxes, trying to get the AMA to pay for everything, find hotels, transportation and the penultimate achievement : participate in an International Team Managers meeting where minutia of rules are argued vainly in English, each TM trying to gain advantage for his home team. After that, you get to sit in the sun for a (2) day toy airplane contest followed by a (4) or (5) day toy airplane contest!

Between his and my retirements, Chuck and I were discussing work at North Island. After several organizational changes and reorganizations we both concluded that I in fact occupied the closest thing that remained to Chuck’s former position in charge of Aircraft Avionics Engineering which was a country mile from where we were when the club was started. Hmmm, how did Chuck manage to hand me down his old Federal job?

After excusing himself from shepherding any more US FAI-F5B World Championship Teams, Chuck took on the equally thankless task of leading the US FAI-F5 Team Selection Committee. This fun job involves developing and maintaining various Team Selection Program Plans, seeing to it that proper US World Championship Teams are fairly created via sanctioned competitive events and the winning Team Members names are dutifully conveyed to the AMA.

Sometime after Chuck’s health deteriorated, Steve Neu twisted my arm into taking on the task of US FAI-F5 Team Selection Program Manager…wait a minute this was Chuck’s job! Dang it Chuck, you did it to me again! And I wouldn’t have had it any other way. We’ll miss the selfless courage you used to fight illness for many years and your irreverent humor. Wishing you forever blue skies, light winds, perfect landings and batteries that always stay charged. Goodbye old friend.

Spektrum Transmitter Switches

For those of you who have maybe jumped up and down on your transmitter screaming bad words after a bad landing, or just knocked the TX off a table, there are a few sources to get replacement switches.  Thanks to Frank Sutton’s efforts to get replacement switches for Alex’s transmitter (knocked off a table) your search is made easy.  Here is where they got theirs:

JK Electronics’ Website is at this link:
JK Electronics is located just off I-405 and the address/phone number is on their Website.  I don’t have the part number, but I’ve attached two photos showing both sides of the replacement toggle switch. One side it states “D Q 11” and on the other side it states “ON  OFF ON” and “2A 250VAC”, then “5A 120VAC”. This is the same thing in our Spektrum Transmitters. The price was right too, just under $3 each!


Brad found some transmitter switches at Digikey:

The website is

The 3 position long round switch – usually flap:
The 3 position short round switch :
The 2 position long flat switch:

WWII American Spitfire Pilot

An 18 year-old just out of high school was trained to take pictures of damage done to German targets  by B-17’s. He flew in a British Spitfire fitted with extra fuel tanks where the guns were. In other words, he flew over Germany unarmed…

WWII American Spitfire Pilot…

This is probably one of the best WWII film clips out there. Stored for 61 years in two suitcases of 16mm home movies that were inherited by filmmaker William Lorton from his great uncle who served as a Flight Surgeon. Those suitcases contained 3 hours of war footage that included a compelling crash landing of a Spitfire in 1944

Filmed in a 2005 interview with the now 83 year old pilot and seeing the expression on his face when he realizes it is him in the cockpit, is something you won’t soon forget.

At 18 years old, he was all alone, behind enemy lines, with no guns, no escort, and he gladly did it.

They just don’t make them like that anymore. It was truly the greatest generation and we owe them so much.

Two FAA Emails Regarding Remote ID

For Immediate Release
May 5, 2020

WASHINGTON – The U.S. Department of Transportation’s Federal Aviation Administration (FAA) today announced the eight companies that will assist the Federal government in establishing requirements for future suppliers of Remote Identification (Remote ID). Remote ID will enable Unmanned Aircraft Systems (UAS), commonly called drones, to provide identification and location information while operating in the nation’s airspace.

The FAA selected the following companies to develop technology requirements for future Remote ID UAS Service Suppliers (USS): Airbus, AirMap, Amazon, Intel, One Sky, Skyward, T-Mobile, and Wing. These companies were selected through a Request for Information process in December 2018.

“The FAA will be able to advance the safe integration of drones into our nation’s airspace from these technology companies’ knowledge and expertise on remote identification,” said U.S. Transportation Secretary Elaine L. Chao.

This initial group will support the FAA in developing technology requirements for other companies to develop applications needed for Remote ID. The applications will provide drone identification and location information to safety and security authorities while in flight.

The technology is being developed simultaneously with the proposed Remote ID rule. Application requirements will be announced when the final rule is published. The FAA will then begin accepting applications for entities to become Remote ID suppliers. The FAA will provide updates when other entities can apply to become qualified Remote ID USS on

Drones are a fast-growing segment of the transportation sector with nearly 1.5 million drones and 160,000 remote pilots now registered with the FAA. The agency’s ability to develop Remote ID technology simultaneously with the rule enables the FAA to continue to build on a UAS Traffic Management (UTM) system that has demonstrated global leadership through the small UAS rule and the implementation of the Low Altitude Authorization and Notification Capability (LAANC), which automates the application and approval process for most UAS operators to obtain airspace authorizations.



Remote ID Cohort Information

Thanks for the questions we received after yesterday’s press release on the Remote ID Cohort. To clarify, the Cohort is not part of the decision-making process for the proposed Remote ID rule final rule. The Cohort will help the FAA develop technology requirements for other companies to develop applications needed for Remote ID. The comment period on the Remote ID Notice of Proposed Rulemaking closed on March 2, 2020, and the FAA is reviewing the more than 53,000 comments.

If you are a member of the media, contact us at and a public affairs specialist will respond.

If you are a drone operator with questions about Remote ID, or any other drone-related question, please email or call 844-FLY-MY-UA.

Thanks To Everyone Who Contributed!

When I sent out the request to let me know what you guys are doing on your COVID vacation, I never thought I would get such a tremendous response.  Thank you so much for your stories and pictures.  Never let it be said a modeler does not know how to keep himself occupied.  Below are the articles you sent in during the last couple weeks.  These are your editor’s favorite kinds of things.  I love to share what our members are doing with the readers.  Anything from a picture and a paragraph to full blown build article.  It is all appreciated! – Steve B.

“SEFSD Memories 2019”

(The video above starts 16 minutes from the beginning.  Click on the left end of the status bar to see it from the start.)

Frank Sutton, our intrepid photographer, has put together a beautiful collection of pictures and videos from 2019 for your enjoyment.  He says it best:

“This is the SEFSD 2019 Memories movie, 92 minutes of rocking music, videos and photos covering the flying highlights of the entire 2019 year! We recommend you get your favorite drink and pop some popcorn when you’re ready for that one – and crank your speakers up! Starring in this movie are the Pilots and Planes of Silent Electric Flyers San Diego, and the movie is dedicated to them. We hope that by watching it, the Pilots and their Friends and Families will be able to escape for at least 92 minutes from these uncertain times we’re in now.
  During these uncertain times, we all probably have a lot of spare time on our hands and little entertainment. We certainly can’t go flying! So, it took a national disaster for me to taxi down the runway and get this going, and it is about time too!
  In addition to our San Diego County Dash Cam Spy Channel on YouTube, we have a brand new Channel – Aviator Alex! We already have three short videos and one full-length feature movie ready for your viewing pleasure! Please take a look and give us a “Like” if you like it – and we think you will!
  For the moment, all the videos are with Silent Electric Flyers San Diego and flying via Radio Control (R/C), however, we will soon be adding more videos to include Alex’s adventures flying actual sailplanes a Lake Elsinore Soaring Airfield and Hemet Airport with Cypress Soaring (with a Go Pro camera in the air too!)! I have a lot of photos and videos ready to go, and too much time on my hands!
  Here’s the direct link to the new Aviator Alex YouTube Channel……
  And here’s four videos ready for your viewing pleasure……


Stay tuned, our new YouTube Channel Aviator Alex has just taken off!
Keep your seatbelts on, you ain’t seen nothing yet!”

Our Friend & Fellow Member John Forester

“Remembering John

John was born in London England October 1929.  His father was CS Forester, an author who wrote many books but was known for the Horatio Hornblower series and the African Queen

John served in the Navy for a short term before being honorably discharged.  He earned a Master of Science in 1964

He had three passions in life: Cycling, Taking pictures, and Flying model airplanes.

Cycling was not only a passion but a way of life for him. He started to ride in 1937 in England and then continue when they moved to California in 1940.  He was instrumental for helping to fight the battle against mandatory bike paths in 1972.

I remember him as always building and tinkering.  We made model boats and rubber band launched gliders out of balsa wood and tissue paper which would slowly circle before landing.  He also had several rubber band power planes.  I think it really changed for him with the advances in battery technology and then finally from analog to digital controls.  We would often talk about the issues with the analog controls.  He loved to fly and also to teach in his own style and was never afraid to give suggestions and guidance at the field.  He typically liked to fly on weekdays when it was less crowded so that on weekends other could fly.”  – Geoffrey Forester


I was happy when John come and sat with Alice, Sean & I at a table in the back of the room at the Harbor House this last January.  Little did I know that was the last time I would see him.  I heard from him a few days before he died.  We exchanged a couple emails where he asked if I thought someone from the club, who lived near him, might consider helping him if he needed it.  That was our last conversation.

During the dinner he showed me the response he had written to the FAA regarding their proposed new rules.  Well written, concise and to the point.  I was impressed how well written it was.  I just learned that John has been writing professionally for a long time.  He wrote Practical Cycling which is now in its seventh printing.  

John was a big contributor to our club.  He headed up the flight training program and many of today’s pilots learned to fly under his tutelage.  Maybe you have read his comprehensive article on learning to fly.

I received an email from his son Geoffrey a few days ago telling me he had passed in his home.  John was 90 years old.  – Steve B.


“I remember John Forrester as a kind gentleman and an avid competitor in our EMAC competition series. John rarely missed a chance to improve/demonstrate his flying skills in the BASIC class even though he probably surmised that just taking home his airplane in one piece was a successful endeavor! More recently, John’s reasoned and impassioned letters to the FAA defending our rights to fly our models without restrictions, registrations, etc. became the model for mine and other peoples’ writings on the subject. We’ll miss your charm and wit, John. Hope your skies above are filled with light to no winds, perfectly axial rolls and all 10 point round loops”.  – Steve Manganelli


“John Forester (1929 – 4/2020)

When I first contemplated joining SEFSD, John Forester was one of the members I connected with first.  It turned out that John and I shared a common background as subject matter experts; he consulted about bicycle cases while I worked on accident reconstruction cases.  Once I formally joined SEFSD, it became a weekend ritual for one of us to seek the other out for some good old fashioned flight line chatting.

John was well versed about many topics, but the two I recall the best were aero modeling and bicycling.  John was an engineer and those two fields of interest seemed to suit him to a tee.  Each was a science-based endeavor that clearly kept his mind active and heart young.  I think he was 83 when I met him and, irrespective of age, he was a remarkably good pilot. He even remained an SEFSD Flight Instructor until the last year or two.

I had earned his confidence, along the way, and he occasionally spoke with me about his active consulting cases.  I felt honored that he confided in me as a case-related sounding board and I enjoyed the time we shared together.

John’s influence can still be felt today since he was a staunch advocate for the bicycle transportation industry.  I’m convinced that bicyclists today owe a certain debt of gratitude to John and that many policies were advanced by him.

I’ll remember John Forester as a kind and intelligent person who will, no doubt, be missed.  Rest in Peace, my friend.

Eric Shapiro


Farewell to SEFSD Member Jack Hix

“Dearest friends of Jack,

My name is Sara, and I am Jack’s daughter. This post is to let you all know that, early Easter morning, my Dad passed away peacefully in his sleep. He had been receiving absolutely wonderful care for the past nine days from the staff at Day Break Retirement Villa and Seasons Hospice & Palliative Care. Everyone involved with both these organizations was so skilled at helping us navigate this difficult time under such extraordinary circumstances. We never imagined we would be saying goodbye to him over video chat, but the universe does what it does, and you just have to roll with the punches. I will be forever grateful to the staff at Day Break and Seasons. They made this confluence of events as easy as it could possibly have been considering this previously unfathomable scenario. They are truly gifted care providers, for both patient and family. Though we were not by his side, they were able to provide enough connection to make us feel that, in a way, we were there. From the bottom of my heart, I thank them.

My mom, Mary, has moved in with my brother, Jesse, and sister-in-law, Laura Mae, in Richmond, CA. The three of them are enjoying each other’s company and sharing this experience together with deep love and gratitude for our cherished family. My husband, Joel, and I are able to video chat with them several times a day and, for that, we are thankful. I await the moment when we can all wrap our arms around each other again. There will be tears that day.

Once the shelter in place order is lifted, the five of us will be having a memorial service and burial of his ashes which we will live stream here. I will make sure to provide updates as to when that will be taking place. I know how dearly loved my dad was by so many of you. I know you all treasured the amazing, funny, kind, and endlessly brilliant person he was. Please feel free to comment on this post with any pictures of him you’d like to share or stories you’d like to tell about him. Don’t spare the details. Go on at length. Make us laugh like he would have. Since social media is all we have right now, let’s make good use of it. My love to you all. I know my Dad is at peace, and I hope we can use the connections we make here to bring some peace to each other.

-@Sara Jane Hix”


We lost a great club member recently, Jack Hix.  Most of the current members may have never met Jack, but you would remember if you had.  He has not flown much in the last 10 years or so.  Jack was an outstanding modeler and great story teller.  Always quick with a joke and had a tremendous sense of humor.  I think that is what I’ll miss most about him.  I remember him coming out to the field so pleased with his latest creation and ready to show it off.  His attention to detail was inspiring.  Some of his models are shown below like his Mini-Mamba, Old Timer, etc. 

For those members who were around then, Jack provided his expertise as a graphic designer to create the wonderful logos for our yearly events such as the Mid-Winter Electrics, Spring Fling or Fall Fun Fest.  Some of his designs are below.

I can still hear his laughter. – Steve B.


“As for Jack Hix in addition to him being a most excellent modeler and builder of miniature airplanes it he was also the the leading pool shark of, I think he lives in Vista, but the local senior center he regularly clean them out of a couple hundred dollars a night just shooting pool with them.” – Wayne W.


Treasurer’s Report for April 2020

Business is still getting done at SEFSD even with Covid-19. First off, I want to thank the members that continued to join our club even after the city closed the parks in in Mission Bay. All of your support is appreciated! We are at 253 members. As of April 23rd, we are still closed, but look for reopening announcements. Just FYI, we have temporarily suspended service on the port-a-potty until the field reopens, so if for some reason you go there (which you should not) and notice a lack of service, that’s the reason. When we do reopen, we plan to do maintenance on both the runway, and the parking lot. We’ll have 50 – 60 gallons of dust control to soak the entire field and parking lot to get everything in good shape again. Our charter has been renewed, as well as our insurance policy for the city. We’re still waiting to hear back from the AMA to see if we got any money from the Flying Site Improvement Grant. 


Who Needs a Stinking Runway?

Bob Stinson here. Many of you have seen some of my unusual aircraft at the field. Words like “crazy”, “what the heck is that?”, and my favorite “of course you’d have one, Bob”, have been heard often over the years. Well, there was a method to my madness! What would I do if the field was closed down? Vertical flight was the answer. Of course, I wasn’t expecting the culprit to be a virus.

I’m fortunate to live on a cul-de-sac, and on the edge of a canyon. I’ll fly drones over the canyon and helis over both. Happily, neighbors are tolerant of my toys!

Stay safe and healthy everyone. See you all when this is over.

Wayne Walker’s Sailing Adventures

Wayne bought a sail boat in 2018 with the intent of sailing from the East coast down through the Panama Canal and on into the Pacific.  The trip has had some starts and stops due to mechanical issues.  Last year he made it to the South of Florida.  This winter he has finally made it to the US, Virgin Islands.  Here are his latest comments as of April 13th:

“I’m trying to get to the US Virgin Islands after getting chased out of Jamaica and not allowed into Puerto Rico.  Great sailing so far, Wayne

I made it to Saint Thomas island in the US Virgin’s yesterday so all is well.  Things are not bad here at all, everyone’s taking the quarantine business seriously and being being good about it I guess is the best way of saying it.  I’ve got to get a place to haul the boat out and leave it here for the hurricane season so that’s my job for the next week or so.  All is well everything worked out, talk to you later bye-bye”

The prequel to this story can be read on his blog.  His latest entry was on Jun 2019:

How to Size a Jet Exhaust Cone – Math Method

By Steve B.

I needed to make a small conical shape from a flat piece of plastic.  I had replaced the small jet fan in my Kyosho Jet Vision since the original fan shucked a few blades on takeoff (FOD).  The new fan was bigger so it needed an adapter to fit between the fan and rear half of the exhaust cone.  I could do it with trial and error but I wondered if I could figure out the math and create it in my drawing program, and I did.

The part I made was the amber colored piece between the blue fan and the black tail cone. The fan assembly is pulled forward so you can see the cone. Normally it sits all the way back.


The part before installation.

I’m sure there are any number of places online that have this already figured out, where you can simply input your measurements and voila you get the answer.  I didn’t look.  I wanted to see how it was done.  My only external source was my lovely retired middle school math teacher wife, Alice, who provided some of the basic formulas I had forgotten.  Although, when I had a question, I did have to raise my hand and wait my turn. . .

Remember sitting in Middle School (Junior High) Math class and wondering what you’ll ever use this stuff for?  Well, this is a great example where you can use both Geometry and Algebra.  Sound like fun?

A typical exhaust cone will look something like these.  The long one fits my Avanti jet and the other is for my Jet Vision:

The cone template on the left is for the Avanti and the right one for my Jet Vision as seen above.


My drawings were done in a computer drafting program.  You can also do it by hand using a compass, protractor and straight edge.  You may need to commandeer the dining room table if your workbench is loaded with stuff, like mine.

Using my Avanti jet as an example, I created this drawing.  I know the Avanti does not need a tail cone, I just used it for an example.  The calculations are below:

This shows all the geometry involved. The part we are interested in is the small segment at the right.


This is the segment that gives us our cone template.


This is the math used to create the drawing:

What we know:

   <1 = <2  (Angle 1 = Angle 2)

   R2 = R1 + Lc  (Radius 2 = Radius 1 + Length of Cone).  (R1 & R2 are radii used for the layout above.)

   Arc1 (Arc length 1)  see just below

   Arc2 (Arc length 2)

The arcs lengths are the circumferences of the ends of the cone.  For their radii, just measure the diameters of the fan and outlet and divide by 2.  (ro1 = radius of outlet, rf2 = radius of fan.)  The arc lengths are:

eq. 1   Arc1 = 2π ro1 and Arc2 = 2π rf2

Now all we need to find are <1 & <2 and R1 & R2 in order to create the layout.  We know the relationships between the angles and between the radii.  This gives us only two unknowns.

Now we just need two equations.  Solve for one unknown in one equation, substitute that into the other equation and solve for the other unknown.

eq. 1a   (<1÷360) 2π R1 = Arc1

eq. 1b   (<2÷360) 2π (R1 + Lc) = Arc2

Lets solve for R1 in eq. 1a:


eq. 1c   R1 = Arc1÷(.0175<1)

Substitute that into eq. 1b and we get: 

   (<2/360) 2π (Arc1÷(.0175<1) + Lc) = Arc2

Lets solve for the angles (<1 = <2):

   (.0175<2 (Arc1÷(.0175)<1 + Lc) = Arc2

   Arc1 + .0175<2 Lc = Arc2

eq. 2  <1 = <2 = (Arc2 – Arc1)÷(.0175Lc)

The Arcs and the Cone Length are measured quantities, so substitute them in to find the angle.

Now find R1 by substituting the angle into either eq1c.

eq. 3  R1 = Arc1÷(.0175<1)

Here are the numbers needed to make the drawing above:


ro1 = 35mm, rf2 = 41.5mm

Lc = 365mm


From eq1:  Arc1 = 2π ro1 = 220mm, Arc2 = 2π rf2= 261mm

From eq2:  <1 = <2 = 6.419 Deg

From eq3:  R1 = 1958mm, R2 = R1 + Lc = 1958 + 365 = 2323mm

These highlighted values are what you need to draw your exhaust cone.

How to Size a Jet Exhaust Cone – Layout Method

This method is a bit simpler than the previous method.  It involves little math but may require the same clearing of the dining room table to make the layout.

It was sent in by Bruce Brown, club member, expert aerobatic pilot, retired sheet metal Journeyman and all ’round great guy.  I’ve flown aerobatics with Bruce for many years and when I want to know exactly how a maneuver is suppose to be flown I just watch him, usually followed by “Oh, that’s what it’s supposed to look like. . .”  

Bruce:  “If the cone adapter for the jet exhaust was your project then here’s how I would have done the layout, just as I did at work for 36 years. (Step 1) Draw a vertical centerline, then an outline of the fitting or “side view” of cone, bottom being the big end (D2) and the top (D1) centered above it by the length of the cone.  Then draw lines through the end points of D1 & D2 and extend them upward until they intersect. (Step 2) This is the point (Vertex) to then swing arcs through the same end points of (D1 & D2). Multiply D1 & D2 each x π to get their circumferences, which are also the arc lengths (Arc1 & Arc2).  With a flexible ruler, measure half the circumference (arc length/2) to each side of the centerline along the arcs drawn.  Then from the ends of the arcs, draw lines back to the Vertex. (Step3) You now have the pattern.”
I provided these drawings to help visualize the process.  I added the references in Bruce’s instructions above.  This is the adapter for my Jet Vision mentioned in the previous post.

San Diego Dash Cam

The MAY2020 San Diego County Dash Cam Spy video #25 has been unleashed early to help fight the boredom some may have due to the ongoing COVID-19 Crisis and upside-down uncertain times!  Stay tuned to the very end for some Breaking COVID-19 News, you’ve got to see it to believe it!  – Frank Sutton

Let’s Help Out Our Local Hobby Shops During This Difficult Time

Franks Gagliardi sent this letter out to a few folks.  He certainly captured to sentiments of many others.  Here is Frank’s letter followed by a couple responses.  Please see here for a list of the Local Hobby Shops.


I was thinking about John Weaver today and wondering how Discount Hobbies was coping with the current crisis, so I called him and could tell by the tone of his voice that he is concerned for the health of his employees and his business and rightfully so. We as modelers have an advantage over those who are coping with home-bound restrictions. We can dream, read, build and converse with fellow modelers. We can also help our local supplier and friend by patronizing his business when possible and not taking the “easy way out” and shopping on line to strangers that we don’t really know and who may or may not be there when we need help or advise. So, let your heart be your guide during these difficult times and remember who we depend on to keep us happy!

Semper Fidelis

Frank Gagliardi”


David wrote:

“Great email Frank!

I was over there on Monday and bought 3 BNF Eflite planes.   Air Tractor, P-39 and the Extra 300.  With plenty of time on my hands Ethan and I have already had a few flights with each!  

To the rest of you, get out there and pick one up!”


Eric wrote:

“Thanks Frank I picked up a little toy myself there. absolute best cure for COVID-19 in my front yard”