Alex's IC-power 3696 at 2007 NATs

You got a cool electric WWII combat rig? This is the place to show it off!

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Alex Treneff
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Alex's IC-power 3696 at 2007 NATs

Post by Alex Treneff »

After I flew my internal combustion powered 3696 Wildcat at the 2007 NATs, I got e-mails from a couple of guys asking me to post all the details on the forum, saying they would have tried 3696, but thought they had to use electric propulsion. This will be a thread to discuss the up-to-now unexplored IC-possibilities for 3696.


My F-4F wildcat was quickly-built. It was scale straight from the CAD files, just lacked a very scale paint scheme, since I finally finished it midnight before we left for the NATs.

With the plane scaled to the 36" maximum wingspan, the prop-to-hinge length was 24", right on the minimum.

The fuselage was two 2" pieces of foam joined vertically, giving the finished width of almost 4". I cut it horizontally down the fuselage just above the wing and glued a 1/8" lite-ply sheet the entire length with probond. After sanding the fuse to shape, I epoxied a 1/8" lite-ply firewall on the front and bolted a motor-mount on.

The wildcat was powered by an OS .10FP, which at our field turned close to 10,000 rpm with the spec prop, but only 8,600 rpm at Muncie. For the next tests I will use an OS .15LA.

I used an Electron 6 receiver right behind the wing. I used a 4-cell 700 maH Ni-Mh battery, right in front of the wing. I used 3 HS-81MG servos, which could be replaced by lighter servos and save an ounce or so.

I needed a 2-ounce tank to get the full 6-1/2 minutes of flight time. It was installed directly in front of the canopy.

The tail sections were 4-mil coroplast held on by balsa triangles for the test model. When I mid-aired with Lee the glue held but the balsa broke. I will find a better method to attach them in future.

I had a painted 2-liter pop-bottle cowl attached, but removed it after the first test flight. It wasn't attached very well and we weren't sure if it was part of the stability issues. Most of the problem turned out to just be the wind, tail heaviness, and 400 RPMs.

The plane came in about an ounce or so over the minimum, but flew well, considering it was 400 RPM below the other three planes flying. Mine also needed a little more nose-weight to balance, which the .15LA will help with.

I've got pictures of just about every step of construction and the finished plane, so I'll post some of them once I get them all off my camera and sorted out.

I had a lot of fun flying 3696. The scale-factor is cool, and the planes are fast enough to be easy to fly, but slow enough to have some pursuit to the game. Lots of fun! [8D]
RH
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Post by RH »

Alex, you are a not in the box thinker [}:)] Although I thought 3696 was all about electric, I have a .10LA just itchin to cut some streamers. Thanks for jogging my thought process.....
Alex Treneff
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Post by Alex Treneff »

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by RH</i>
<br />Alex, you are a not in the box thinker [}:)] Although I thought 3696 was all about electric, I have a .10LA just itchin to cut some streamers. Thanks for jogging my thought process.....
<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">

No problem Randy. You are about the 4th guy in the last few days to tell me something like that. The more the merrier!

The .10 will probably work as long as it's not too hot. It was pretty hot in Muncie the day we flew 3696 and the .10 wouldn't quite hit 9,000 on 30%, but at our field a couple weeks earlier it was a little cooler and the .10FP hit over 9,000 on 20% if I remember correctly. See what she'll do!
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Post by adamdb »

Alex,
Very cool! I would have thought that a .10 would have a hard time with a 9x6 prop, but it sounds like it handled it fine. Hmm, I've got a .10FP looking for a home...

Adam
RH
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Post by RH »

Alex,

As much as I admire your thinking process and, thanks for getting me to thinking, I would like to encourage you to put an electric on your 3696. The whole concept of 3696 was to get the e-park flyer folks interested in a class they could compete in. I am not sure if you are flying any electric yet but if not, you should give it a go. My 3696 is in the car all the time, comes out and flies first or may be the only thing to come out and fly. No start up gear required. Plug and play man! They are fun!

r
Alex Treneff
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Post by Alex Treneff »

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by RH</i>
<br />Alex,

As much as I admire your thinking process and, thanks for getting me to thinking, I would like to encourage you to put an electric on your 3696. The whole concept of 3696 was to get the e-park flyer folks interested in a class they could compete in. I am not sure if you are flying any electric yet but if not, you should give it a go. My 3696 is in the car all the time, comes out and flies first or may be the only thing to come out and fly. No start up gear required. Plug and play man! They are fun!

r
<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">

E-flyers compete perfectly with IC 3696's. They both have the same RPM, prop, weight... actually, they are practically identical. I don't have the time or money to figure out electrics right now, so I'll stick with the .10's and .15's that I have and know how to run for now. [:)]

I am going to try the .15 on my F-4F since it is already built, but plan to build a P-51 to replace the F-4F. The F-4F was built in a hurry as a test model, and as a result is not that pretty! [:p]
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Ed Kettler
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Post by Ed Kettler »

Alex, you might want to hook up with Mark Cipilone who is trying to get interest in 1/2A scale.

While you claim that there is nothing in the guidelines for 3696 that prohibits IC, you are conveniently ignoring a lot of hard work and effort by many people to develop this electric class, as evidenced by the many threads and hundreds of posts, not to mention personal investments of time and money. It even says "Electric WW II Fighters" in the header of the Forum area.

Put one of the electric combos in your next plane and join the fun![:D]

My $0.02
Tim Treneff
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Post by Tim Treneff »

If you look at the 2007 NATS paticipation there was one electric SSC pilot for 27 I.C. SSC pilots which is about 3.5% and was made possible by a board voted wavier of the SSC rules.

The 3696 demo had one IC pilot for 3 electric pilots which is about 25% participation.

Gee, I guess we need the board to vote a 3696 emergency wavier to let IC in 3696 like the one that put electric in SSC (is 3696 a provisional class yet?).[:D]

By the way, most of the noise on this subject is coming from folks that were not there or didn't participate.

Lee was there and his comments were favorable. What did Mike or Bob think? Most folks there didn't even know there was an IC flying with the other three electrics.

What is the objection from the bench? The noise from the .10 at 8600 rpms was as quiet as the electrics and to me less irratating due to the absence of the electric motor whine. IF RPMs is RPMs, weight is weight, and size is size, what's the beef?

Lee has proven that he can be competetive no matter which propulsion he uses, IC, electric pusher and electric tractor.

Personally I think SSC was envisioned to be an IC class and should still be restricted to IC planes. Electrics do have a real advantage over IC since electrics can restart in flight after a mid-air when most IC's go dead stick.

If we separate all classes by propulsion type then I'm ok with 3696 to be redefined as all electric. IF not then what's good for the goose is good for the gander. Would 3696 combat at the NATS have been more fun with three planes rather than four?

It looks like the perfect IC engine for 3696 would be a .15. How many folks out there (including many park fliers) already have .10's or .15's that could get them in the air right now at minimal cost?

Someone posted that the IC participation is destroying a large amount of research done for 3696. I think Alex and I might have spent an hour one sunday testing various IC engines![:)]

We should be more concerned with the fact that the biggest class at the NATS was a provisional class and it only had 28 pilots. Maybe yet another nich class will fix that?[?]
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Post by Rabbit Leader »

I agree with Ed and Randy. Although I applaud your efforts, the 3696 birds we're designed as an electric class to promote clean, quiet scale e- combat. The main problem with a .10 or .15 pulling a 9-6 is that is a LOT of prop to pull for that size engine, and I have a feeling that is going to put an awful strain on the piston, wristping, and front bearing/bushing. Not to mention that it would probably be doggone near impossible to make power at higher altitudes, where the E-planes don't seem to be bothered at all.

You want easy? Get the Electrifly 35-36-1000 outrunner, a decent 25 amp speed control, and the Commonsense 2000 packs, and have at it. That's the setup I prefer, and although it's a bit more pricey, the motor is only taching about 300 over the max on a "hot" charge, and it's way easy to dial it back with the atv. Plus it
s a rugged little motor...just ask my Brewster...
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Post by RH »

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">Gee, I guess we need the board to vote a 3696 emergency wavier to let IC in 3696 like the one that put electric in SSC (is 3696 a provisional class yet?).

By the way, most of the noise on this subject is coming from folks that were not there or didn't participate.
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Tim, I'm real sorry that I could not make the NATS this year but that doesn't mean I must remain silent about an idea that I have been promoting and active in for many months now.

It sounds to me like you have a beef against the SSC electric waiver and this is your way of expressing it.

If you truely think IC belongs in 3696 lets hear positive arguements supporting your position not stuff that you disagree with that has happened in other classes in the past.

r
slam
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Post by slam »

first off i agree with others.......way to think outside the box alex.

i had never considered i.c. for e36. does it turn my stomach......hell no. (disclaimer; i will not touch a slimer e36 but will admire it from a distance)[}:)]

the more planes flying the more fun it will be. if someone wants to fly i.c's more power to them. the argument that the motors won't last is immaterial, who cares?

it won't fly at altitude....then they'll fly electric.

the only argument that i really find valid is one that drew and i have considered. this is the only event that could be held at an all electric field. perhaps a stipulation that allows i.c. if it is allowed at the field.

i think that anything that gets more in the air......is something that we need to encourage.

btw, if your plane gets any slime on my plane i'll be mad[:D]

let's fly

slam
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Post by Rabbit Leader »

The only real fear i have is that this will turn into the waning days of 2105. Guy's can't make rpm, or the engine won't last, or whatever. Then we get into a "i want more power" scenario, and we ruin this like we did with 704/2105. Please don't tell me I don't know what I'm talking about, as I was there..(been doing this for over 7 years now). With the electrics, there's no lean runs, fuel draw issues or altitude problems that could frustrate a pilot. Not that there can be problems, there are, but as tested these planes fly better and more relably then my old 704 ME109 with a MAG15 up front.
I also don't want to see this scenario..a displacemsnt limit is decided, and let's say we go with .15...somebody says "you electric fellers don't have "displacement" per se, how do we regulate YOU guys"
and then the fight is on. All we have to do is show how many watts we're putting out with a Wattmeter, and that we only tach 9 grand, we should be good, right? You would think that would settle it, but it probably won't. Then we'll argue back and forth about how much of an "advantage" and electric setup has over glow, etc, etc, and this proposed class will be dead before it has a chance to breathe.

That's just some of the scenarios that are going thru my mind, and they are based on the constant bickering that goes on about electric in general, and the horsepoop that was bandied about to ruin the old 704 class, which turned a nice sclae class into a sky full of overweight rocketships. Now, we might have learned a thing or two from our past, and if we have, and we can run up a set of rules and regs that allow both IC and E-power to comfortably fly side by side in 3696 without RUINING it, then let's give it a go. I just dont' see it happening.

BTW, I thought real hard about putting a 15 with an 8-3 on one of my planes a few months back, but after thinking about it, I decided against it, for the reasons stated above.

Also, this smacks real hard of building a plane to procve a point, not neccesarily a concept, which in my books is politics. Sometimes I think that if Jefferson Smith was an RCCA member he would have given up the ghost a long time ago...[:(]
Tim Treneff
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Post by Tim Treneff »

Cash, the beauty of the 3696 rules at present is there is no stipulation of power plant other than the specified propeller(s) and RPM's whether it be electric or IC. If an electric guy needs more cells to get RPMs he can. If an IC guy needs more power at altitutde he could use a larger displacement engine as long as either only turns 9000 rpms (for single). There shouldn't be an arms race as long as the prop and rpm's is limited.
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Post by jpmorere »

Several points...

When SSC was conceived electric power was not even a consideration. The state of the art electric technology available to the modeling public at the time simply was not up to the task and thus was not even on the radar for those who conceived and developed SSC. Times have changed and so have electrics - they have been proven viable in SSC, 2548 and even open B. They do suffer their penalties as well. They cost more, and in order for the aircraft to be built to a competitive weight the airframe MUST be built lighter and more fragile than glow power aircraft. Enough.. This part of the argument belongs in the SSC forum not HERE in the ELECTRIC forum..

E36 or e3696 (whichever you wish to call it) was conceived as an ELECTRIC class! The idea was to have aircraft that were relatively simple to maintain, prep and fly, and be flown in places where glow power is not acceptable. With the exception of charging battery packs (transmitter and flight), these aircraft can be taken out and flown on a moment's notice - whether for sport or competition.

We don't need any waivers to do what we want, because this is still a concept development - not even a provisional class as far as I am aware. There is a core group who were the initial developers of this class and they have the final say. Comments and suggestions are being taken, but the core group (not the RCCA membership at large) make the rules. They could say anything - No glow, No electric, fly anything regardless of what it looks like or how it is powered, whatever and NOBODY BUT THEM truly have anything to say about the rules.

Any more demands for this emerging concept class??

J.P.
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Post by Rabbit Leader »

There's one other minor problem with an IC in 3696. The spec prop is a MA 9/6, which is pre-drilled for a 1/4 in hole. The old FP engines used a 1/4-20 propnut on a 1/4 inch shaft. The newer LA series, and the magnums, are 5mm. You'll have to find or fabricate bushings for the 5mm crank...
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