Chairman’s Corner for Apr – May 2022

By Jovi Murek

Hello Members and new members who I have met down at the field in the recent weeks, I welcome you to our club.  Here at the SEFSD you will find a lot of guys who are passionate about flying model airplanes and are extremely friendly in helping out with any questions you may have.  I invite you all to attend our monthly meeting which we hold on Saturday a week before the end of the month!   We have fun flys which are coordinated by Jim Bonnardel who puts on a great event.  So please join us! 

Speaking of our Monthly meeting that is happening this weekend, please come and enjoy the fun with our members.

It’s hard to believe but we are at the end of April all ready, man time is flying by so fast!  July 4th is coming up soon and the BOD is working on putting an event together.  However we will not hold it on the 4th which is a Monday, we’re going to hold it on Saturday the 2nd.  This way we won’t have to deal with traffic and people parking in our lot, which if we did, the gate would be locked and our field would not be open to the public.  Now our members are more than welcome to come to the field on Monday July 4th to watch the fireworks, just remember to lock the gate as you come in.  The field is only going to open for Club members and families only.  If you do plan on having a cookout, just remember that charcoal BBQ are not permitted at the field as well as NO Alcohol or drugs which the city and the club does not permit. You’re welcome to bring a small propane grill, kinda like the one we use for our monthly meeting when cooking Hot Dogs!  And please be safe if you plan on coming to watch the fireworks.
It looks like we just might be getting closer to improving our runway and I hope to have the final details for you by next month.  We do still need permission from the city and we are also working on getting our presentation completed in the next few months.  Again more information coming soon!
I would like to thank Alan Isaacs for taking on the position of Treasurer for our club.  Thank YOU Alan!!   It does look like we are in need of a Secretary role for the club.  Currently our President Steve Managanelli is subbing in for this duty.  I invite any member who would like to step up and be a member of the BOD.  If you are interested please see me (Jovi) or Steve Manganelli or our Vice-President Quan Nguyen.,  Speaking about Quan, he has re-upped our club membership with AMA.  Thanks for getting that done Quan.
The winds lately have been coming out of the east and then changing to the North-west or South-west.  It just comes in all directions.  We as flyers have to fly in either two patterns, If the wind is coming from the east we are in a take-off and landing counter clockwise, left to right.  If the winds change, so does our pattern. This does not mean that you can continue to fly in the pattern as if the wind was coming out of the east.  Please observe the direction before you decide to take off.  We don’t want flyers flying in the opposing direction and having midairs!
Safety note:  Our field is getting dry and we all need to be careful if we happen to crash our planes.  I urge everyone to get a fire extinguisher to have at the field.  I have two available that I can give to club members who fly often at the field.  IF you’re interested in having one come please see me!
UCSD is going to have an event at our field on June 10th from 8:00 am to 12:00 pm. This event is going to be a Scoring Function as a weighted sum of max speed and payload.  They will have 4 groups of 4 – 5 students and each group will build their own aircraft that are designed from scratch.  These aircrafts will have about 3 foot wingspan and will all have Cobra 1180 Kv motors with ESC along with a 3C (11.1) LiPo battery.  I invite you to come out and watch the event.  If they are in a down time our member may fly in that time, but once they are ready I kindly ask you to give them the airspace.
Last note we are going to change our Logo.  It’s been some time and many members as well as the BOD agrees to change it.  Along with changing our logo, we are also looking into getting Tee-Shirts and hats made too.  The final details have not been decided and we are getting a sample made.  Once we receive it, then we will have more details for you all.
Ok, I look forward to seeing you all at the field and hopeful at this month’s club meeting.   My DC-3 is currently under construction and I have more on that to share in this Newsletter.
Happy flying to all our Club Members.

President’s Corner for Apr – May 2022

By Steve Manganelli

Be careful what you ask for, you might get it! This silly phrase applies to the much celebrated field improvement we’ve been discussing over the past few months. Thanks to the hard work of Larry Kosta, costs are within our reach, but the actual logistics of getting it done are significant and the 500-pound-gorilla-in-the-room question is exactly what would be the long term benefit? Let’s face it: the field is dirt, it will likely always be dirt and adding decomposed granite (dg) is just more dirt! I recognized some sample dg material as that used under my artificial turf. When that was applied by professionals using screeds and compacted using a portable plate compactor it certainly formed an airplane happy smooth surface. It could be walked on (if you were careful) but without the turf topper is certainly nothing that would hold up to being say driven on, poked at with tools, or even walked on repeatedly and randomly. Prior to the turf install, but after the dg, animals significantly disturbed it in a few places illustrating just how fragile the material is. Perhaps if there was a binder additive, it would be better? The bottom line is, the BOD voted to defer action on the project until we can find a precedent for the application for a similar purpose as ours. In the meantime we’ll go forward with our usual “mid-Summer correction” meaning water truck, dust down, and rolling. If anybody knows of an R/C field topped with compacted dg please let us know!

The final epilog on our 2022 Winter Banquet was we had a grand time and spent a lot of money doing it! There were 341 members eligible (at the end of November 2021) to attend and 53 did so. The remaining attendees were family members and guests. Therefore with less than 16% participation, it is imprudent to spend a lot of Club funds on the banquet. As of now, we’re looking at Phil’s BBQ Event Center (same parking lot as Phils BBQ, Pt. Loma) with a per member cost of $25 and a guest cost of at least $30 and a lesser (but still attractive) prize budget. An anticipated turnout of 75 to 100 people will keep us in line with historical expenditures on the banquet. The event will be held early to mid January, 2023.

This Saturday’s  “3 Ring Circus” fun event, cleverly concocted by Jim Bonnardel will be recognized by 3 medals awarded for each sub-event plus the usual Discount Hobbies gift certificates. You won’t want to miss that one, however I will! The American Institute of Aeronautics and Astronautics Design-Build-Fly (AIAA DBF) competition for teams of undergraduate College students takes place this weekend in Wichita KS.  Steve Neu (Pilot) and myself (Design Advisor) will be with San Diego State University with their “Quetzlcoatl” aircraft do to battle with Engineering Colleges from around the country and around the world. See this link for details AIAA Design/Build/Fly | AIAA.   Thanks to Chairman of the Board Jovi Murek whom will be conducting the member’s meeting this month.

We will start running the gates with super high powered “hot liners” on the Federation Aeronatique International (FAI) Class F-5B Motor Glider distance course in early May. Some details are contained in my last column but notably, the field and the drone course will be closed to sport flying while this is taking place. Closing the field to practice doesn’t mean closing the field to other members with “hotliners” wishing to try their hand at the course. We highly encourage that and will be happy to provide coaching on this challenging international event to all comers. This is done on a Sunday afternoon to minimize impact to sport flyers. Watch for the announcement blast.

Meeting and Contest for April 2022

April’s Club Event:
3 RING CIRCUS!
We are doing something new for April
A 3 Ring (event) Circus!

Ring #1: Limbo Loops
Ring #2: 30 second power to dead stick landing
Ring #3: Figure 8 Taxi race

For March’s 3 Ring Circus, we will use the typical, 3-cell airplanes under 50″
wingspan. Trojan, Cub, Timber, Visionaire, Apprentice, Extra 300 etc. No motor-
gliders, no drones, fixed wing only. 3 Cell, 2200 mah battery aircraft is desired.

Limbo Loops = Looping around a limbo ribbon 10ft AGL
30 Second to Dead Stick = Power on for 30 seconds. At power off, timer is
started. Longest glide to scored landing using Electroglide target. Off runway
landings do not score.

Figure 8 Taxi Race = 3 laps around 2 cones without leaving the ground.

Jovi’s DC-3 Build Project: Chapter 2, Building the Top Section

Framing the fuselage Top:  Fun part about building Top Flite kits is that you build right off the drawings. Got wax paper, laid it down and I grabbed all the formers including grooved main stringers.  These two stringers I soaked them in water to create the fit of the curve for the nose of the aircraft.  Pinned it to the board and let it sit.  I also installed the cabin crutch to help form the main stringers.  Once that was done, I then completed pinning down the stringers to fit the drawing.   Next was to place the formers into place just to fit, but not yet glued in place.  Here is where I had to create a hatch for the battery, instead of taking the wings off like I have to do with my Cessna. I replaced two formers.  The formers that come with the kit are 1/8” So I will be replacing them with a ¼ “thick.  These two formers will be used for the opening of the hatch.  The formers that came with the kit are going to be used for the hatch as you will see in this process.

DC-3 Fact:

Without a modern passenger plane.  TWA was not about to let United Air Lines corner the entire market with Boeing’s 247.  TWA initiated a program of their own to develop a modern airliner.  Douglas responded with the most advanced and the most controversial design, namely DC-1.  TWA ordered one unit and in 1933 the first DC-1 rolled off the assembly line in Santa Monica, California.  The DC-1 was bigger and sleeker than any other liner in the industry, including Boeings Model 247!

As you can see in the above photo how the formers were fitted into position.  Starting with the nose of the aircraft is where I started to glue the formers in position.  For the hatch section as I mentioned I am changing the formers with ¼ “thick.  I then cut the two original formers and glued the lower section to the replacement ¼ “formers.  The top half will make up the hatch.  In between the two ¼” formers I cut the middle former to match the hatch and the bottom part, I cut out the middle and only used the sides, also show in the photo.

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3D Wing Loading: A response to Andrej Marinsek

Editor:

I admit it, I am a numbers guy. I gravitate to crunching numbers. I have spreadsheets for my home energy and water use, I designed and built my home solar panel array, at work I used to calculate power budgets for underwater vehicles, etc., etc. Not bragging, just how I am. And it goes equally well for this hobby of model aviation. There are plenty of opportunities for crunching numbers in modeling!

So, when I saw the item in the recent club newsletter “Scaling and Comparing Performances of Aircraft Models (2D/3D Wing Loading) by Andrej Marinsek, I was eager to read it. I’ve been using 3D wing loading in my modeling for many years, and I was very interested in seeing what the author had to say. Unfortunately, my enthusiasm for this useful tool was not reflected in his article.

I don’t know Mr. Marinsek at all, never heard of him to tell the truth. I suppose he is a nice enough guy (he is an aero modeler after all). I could nitpick his article but suffice it to say I don’t agree with his conclusions. Fact is, he doesn’t have a positive thing to say about 3D wing loading, and I just can’t let that go without a response.

The great usefulness of 3D wing loading (3DWL) is it provides a performance number that is size invariant; like 2DWL, it gives an idea of the stall speed and turning radius but is the same no matter the size (scale) of the airplane. For example, I have an FMS Piper PA-18 Super Cub model (1.7 m). It has a 3DWL of 2.9 oz./ft³; the full-scale Super Cub has 3DWLs from 2.3 oz./ft³ (empty) to 5.0 oz./ft³ (gross). Mine is in the range—it tells you something, specifically that the model is going to fly “like” the full scale. My little 1.1 m T-28 Trojan has a 3DWL of 5.2 oz./ft³; it is smaller and lighter than the Super Cub, yet has a higher 3DWL, and that is noticeable in how it flies.

Another example: I’m working on a 1/8 scale model of the Navy’s OS2U Kingfisher, the full-size of which had a 3DWL range of 4.3 to 6.0 oz./ft³. A model weight of 93 ounces would give a 3DWL of 5.0 oz./ft³. I have a target to work toward.

The form of 3DWL I use is what Marinsek calls Eq. 10 (k=1/b x m/S); or what Larry Renger in another article calls Eq. 4 (weight = k x wing area x wingspan or m=k x S x b). Same thing. The units I prefer are the ounces and feet as used above, but any weight and length units a modeler finds convenient will do (and it is weight we measure, not mass, besides which at the earth’s surface and at typical model density, there isn’t a dime’s worth of difference).

The elegance of this particular form, as opposed to the K = m/√S³ form, is its mathematical agreement with another excellent article, “Understanding Scale Speed” by the great Bob Boucher (pronounced booshay). This article is well worth a read. It thoroughly discusses the different numerical aspects of scaling full-size aircraft down to models—including the proper scaling of time! His Rule 2 states “the wing loading of a model built to scale weight will be reduced from that of the real airplane by the ratio of the scale factor.” When a 3DWL value is calculated, part of the scale factor is included (the denominator). When that value is multiplied by a model wingspan, that introduces the numerator, completing the scale factor and voila, you have the 2DWL. Multiply that result by the model’s wing area and you have the model weight. Very neat. The other form is just not as intuitive or handy—how often do you raise a number to the 2/3 power? It is equivalent to my preferred form IF the wing is assumed to be square, i.e., with an aspect ratio of 1 (span = square root of area). It loses the scaling ability. I just don’t see any advantage to it.

The reader who gets to the end of Marinsek’s article is presented with a number of 3DWL limitations (without having enumerated its strengths). Well, yes, sailplanes won’t compare well with warbirds, nor jets with trainers etc. And certainly, there are numerous other factors involved in airplane performance. It is not some “universal field theory” of aero modeling! It is ideal for scaling a specific subject. It is instructive for comparing similar types of models. It’s a useful tool—use it thoughtfully; your mileage may vary; as always, there’s no substitute for understanding!

Best regards,

Seth Mogk

 

Mathematical Conventions Used:

b = wingspan

S = wing area

m = mass (weight)

k = a constant

Fig. 1: My handy scaling spreadsheet—conforms to Understanding Scale Speed formulas

Prop Strike

Here’s something to consider

 Last Saturday during the Electroglide, I had a mid-air collision. This was during a launch where we all send our gliders up at the same time. If we all pay attention and spread out (I didn’t), we don’t have any problems.

 I pulled my Conscendo into a steep climb and into the path of a Radian, also under a full power climb. It was over in an instant.

Take a look at these two pictures. The first is of the chunk of foam removed from the vertical stab of my Conscendo. The second picture is of the recovered foam pieces reinstalled into the stabilizer, notice the gouges caused by the Radian’s prop?   Like I said, it was over in an instant, we only heard one loud whack, but those five gouges are caused by prop strikes. Rather impressive damage in a short amount of time, Eh?

Now, think of your fingers.

Jeff Struthers

Electroglide Report for April 2022

 Nine pilots competed in April’s Electroglide. Weather conditions were not so great with a 13 mph breeze blowing from the North West. This wind made for an exciting first launch. There was a midair collision between Alex Sutton and myself on the first launch.

 My Conscendo pitched hard up. I wasn’t ready for it, so before I could react, I flew into Alex’s Radian.   With a resounding “whack” a large bite appeared in the Conscendos vertical stab and a broken prop fluttered to the ground from the Radian. I was able to keep flying but Alex’s Radian was out of the competition, my bad Alex, sorry.

 The long flight for the first launch was earned by Bob Anson flying the open class at 2:26. I was second at 2:07, also flying open class. Carl Cox, flying in the Radian class, was third at 1:40. Dennis LaBerge (Radian) and Daric Knight (open), both picked up 20-point landings.

 On the second launch, Scott Vance, flying a Radian, had the long flight at 6:20 with a 20-point landing. Bob Anson, flying a Conscendo, was second at 5:45 with another 20-point landing. Carl Cox, with a Radian, was third at 5:20. Dennis LaBerge scored a 30-point landing, Bob Stinson and I scored 20-point landings and Daric Knight scored a 10-point landing.

 On the third launch, Scott Vance again had the long flight at 6:50 with a 10-point landing. Bob Anson came in second at 5:47 and Dennis LaBerge was third at 3:33 with a 10-point landing. I picked up a 20-point landing.

 Fourth and final launch had Scott again showing us how it’s done, flying for 6:52 minutes. Bob Anson was second at 5:05 with a 10-point landing and I was third at 3:20 with a 20-point landing. Both Dennis and Bob Stinson also scored 20-point landings.

 Winners for the day:

 In the Radian Class, First place, Scott Vance, 151 total points. Second place, Dennis LaBerge, 140 total points. Third place, Carl Cox , 42 total points.

 In the Open Class, First place, Bob Anson,  146 total points. Second place, Bob Stinson, 100 total points.

Third place, Jeff Struthers, 96 Points.

 Frank Sutton supplied the pictures of the event; check out the battle damage to the mid-air aircraft.

Next Electroglide is scheduled for May 21st. 10:00.

See you there,

Jeff

T28 Racing Report for April 2022

We had a lite turnout for the April edition of our T28 racing series with 7 planes and pilots present. The preliminary rounds had some hard fought rounds with the lead being swapped numerous times and the leaders being separated by just a few feet. After the  dust settled from preliminary rounds the scores were totaled with the results setting the finals flight groups for the medal round. 
The bronze medal was contested by Larry K and Carl L with Larry taking the win. The silver medal was by far the closest racing of the day between Bob S and Steve M. Bob took the checkered flag by just a few feet only to have a turn judge give him a cut—handing the silver medal to Steve M. The gold race between Brad B and Steve N started out wing tip to wing tip with Steve N getting the lead by the end of the race for the win.
Our next race will be the following Saturday on May 7th at 10am—usual format.
Go fast and turn left!
Steve Neu

SEFSD BOD Meeting Minutes for April 2022

Date and Meeting : Home of Steve Neu, 13 April,  6:30 P.M.

Board Members Present : Chairman of the Board-Murek, President-Manganelli, Vice President–Nguyen, Safety Officer-Neu, Member at Large-Kosta,

Via Zoom : Chairman of the Board-Murek,  President-Manganelli,  Member at Large-Struthers Editor-Belknap

Not Present : Secretary-Dresser, Member at Large-Cox

Called to Order by Manganelli at 6:54 P.M.

Old Business

  1. Membership renewals : 265 as of 4-1-2022. On track compared with 258 at last year’s March BOD meeting.
  2. Club Trailer/ Storage vs divest it : Trailer to remain stored until at least September, 2022. BOD to reconsider at that time.
  3. Banquet expense as compared to membership dues. BOD Decision January 12th : Dues will not increase this year; club finances will be revisited toward the end of the year to determine a prudent banquet expense for 2023 and possible dues increase for 2023.
  4. Raising altitude limit via AMA/FAA sanctioned Safety Risk Management (SRM) Panel. SEFSD is in the queue, we will be appraised approximately Fall, 2023 when we get close to the to the top of the list. In the meantime we must maintain positive relations with Air Traffic Management (ATM) by abiding by the terms of our current agreement!

Field Condition and Maintenance

  1. Field Surface Improvement. One possible improvement under discussion is application of a 2” to 3” layer of decomposed granite and compacting it to a smooth and airplane friendly surface. Larry Costa volunteered to investigate. Update by Larry Kosta :  Cost breakdown is:
  1. Blade……………….$ 900
  2. Roller…………………$ 500
  3. Water truck……..$ 400
  4. Transport ………..$1350
  5. Two Operators…$1200
  6. 200 Yards DG…..$5130

            Total (not Including Water) $9,480

 Discussions centered around 1) City Permission, 2) Long Term improvement, 3) Drainage, 4) Maintainability if automotive vandals, weeds, etc. This exercise has so far focused on getting something done at an affordable cost, now that we have an affordable cost,  a more pertinent question is does any other R/C Club have experience with long term effects/beneift of this process in terms of an existing dirt runway? BOD Decision April 13th : Defer implementation until such a time as it can be demonstrated the result of the process will provide a permanent and lasting improvement to field conditions.

  1. Purchasing more Dust-Down. The liquid dust down, the fluid we normally add to the water when we roll the field in the middle of the Summer is back in stock. We have some in storage, do we buy more now or assume the DG will be the final solution? BOD Decision April 13th : Authorized purchase of approximately $1,000 worth (approximately 20 gallons) while it is in stock and before the price goes up further.

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