Re: CEF speed contest Design Discussions

pkrankow Fri Jan 10, 2014 9:59 pm

I've never had a problem with a plastic tank until it is a problem. lol!

They are cheap, and they are reliable. I am using a tank that is over 20 years old on my test stand without problems. (yes it was used, then put up for 20 years...even had crusty dried fuel residue in it which washed out fine)

Phil

roddie Fri Jan 10, 2014 10:16 pm

of course.. you don't see it in a full-fuse ship.. you two guys (Ron/Rusty) fly classic C/L profile jobs largely... from what I've seen... (I love em") and you don't want a "wart" bulging out of a sleek design.. Better to find a streamlined set-up that works.. and the side-benefit of a nicer looking airplane.

I've got a question.. a friend asked me recently, why not use "epoxy" to put my Speed model tank together with... I honestly couldn't think of a valid reason why not. No tank lasts forever.. it only has to work when you're ready to fly. Test it... if it leaks, swap it out for another. Epoxy is at least fuel resistant. I could build tanks pretty quickly if that would work. The tanks are so small... and my hard-soldering skills are marginal at best. I will try to solder the 4 tanks... but I'm tempted to try epoxy on one of them. Maybe JB weld... I use scissors to cut the bristles short on "flux brushes" for spreading epoxy.. and I could completely seal the tank using one. The holes for the tubing are punched with an awl, and have a deep fillet to support the tubes with either solder or epoxy, and the end-caps have tabs that fit into the ends of the tank body. Maybe thick CA would work... Which is more fuel resistant?

Roddie

**RknRusty** Sat Jan 11, 2014 3:11 am

Nitromethane will dissolve CA, but JB Weld would probably work fine. I think JB is probably a better bond for metal than the epoxy we use on wood. Solder is probably more permanent and soldering improves your soldering skills. Those are the two best reasons I can think of other than aesthetic appeal.

Rusty

roddie Sat Jan 11, 2014 3:58 am

RknRusty wrote:Nitromethane will dissolve CA, but JB Weld would probably work fine. I think JB is probably a better bond for metal than the epoxy we use on wood. Solder is probably more permanent and soldering improves your soldering skills. Those are the two best reasons I can think of other than aesthetic appeal.

Rusty

Yea.... I know Rusty.. I need to practice-solder more.. It's a little daunting... these tanks are so small.. hard to hold in position with anything that won't sink heat away from the work. Maybe wooden (spring-style) clothespin(s) would work.

**RknRusty** Sat Jan 11, 2014 8:24 am

roddie wrote:Yea.... I know Rusty.. I need to practice-solder more.. It's a little daunting... these tanks are so small.. hard to hold in position with anything that won't sink heat away from the work. Maybe wooden (spring-style) clothespin(s) would work.

I'm an expert electronics solderer from back in the days when everything was hardwired or on rather large PC boards, the '70s, but never learned on things like tanks or pipes. My only tank experiment was a mess and I haven't tried again.

OVERLORD Mon Jan 13, 2014 6:28 am

I finished making the landing gear for the Caudron.

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Lieven

roddie Mon Jan 13, 2014 9:27 am

Really sharp Lieven! That's a lot of work there. Is that .060" or .080" aluminum? I like it when people post photos of assemblies, showing the separate components... and once assembled. The gear fairings on my Bearcat are very thin.. (.015" clear plastic packaging mat'l.) and will attach at the top, to the gear-mount blocks with 2-sided thin-film tape... but I'm a little concerned with "flutter"... down low, near the axles. Hopefully the model will fly fast enough, for that to even be a concern! Laughing

Roddie

navion34 Mon Jan 13, 2014 10:54 am

Well done Lieven,

OVERLORD Mon Jan 13, 2014 1:34 pm

Thanks guys, just a sec, got my calculator out

roddie wrote:Really sharp Lieven! That's a lot of work there. Is that .060" or .080" aluminum? I like it when people post photos of assemblies, showing the separate components... and once assembled. The gear fairings on my Bearcat are very thin.. (.015" clear plastic packaging mat'l.) and will attach at the top, to the gear-mount blocks with 2-sided thin-film tape... but I'm a little concerned with "flutter"... down low, near the axles. Hopefully the model will fly fast enough, for that to even be a concern!

Roddie

They're made of 40 x 10 x 1.5 mm L shaped aluminium profile, so yea, that's about 60 thou thickness. The rivets, or what's left of it, are 3 mm dia. Then everything was epoxied together.

Lieven

roddie Mon Jan 13, 2014 4:13 pm

I obtained X3 APC LP 04754 (4.75 X 4) props to test for my CEF speed model. I'm guessing that the hubs are sized at 4mm. There are no adapters that came with them, like their other larger props have. The instructions state: "For 1/4" shaft; use 9/32" and 5/16" tubing for bushing"... so I take it that it's ok to drill-out the hub and bush-it for a 5-40 using the appropriate size Brass tubing sleeves? I did this to one of them already.. carefully, by using a drill press... but if there's something different I should be doing.. I want to know.

I am also wondering what engine/motor with a 1/4" shaft... would use a prop this small... for APC to recommend this?

Roddie

JPvelo Mon Jan 13, 2014 5:34 pm

roddie wrote:I obtained X3 APC LP 04754 (4.75 X 4) props to test for my CEF speed model. I'm guessing that the hubs are sized at 4mm. There are no adapters that came with them, like their other larger props have. The instructions state: "For 1/4" shaft; use 9/32" and 5/16" tubing for bushing"... so I take it that it's ok to drill-out the hub and bush-it for a 5-40 using the appropriate size Brass tubing sleeves? I did this to one of them already.. carefully, by using a drill press... but if there's something different I should be doing.. I want to know.

I am also wondering what engine/motor with a 1/4" shaft... would use a prop this small... for APC to recommend this?

Roddie

I use a small piece of fuel tubing over the prop shaft.

Jim

**Cribbs74** Mon Jan 13, 2014 8:34 pm

roddie wrote:I obtained X3 APC LP 04754 (4.75 X 4) props to test for my CEF speed model. I'm guessing that the hubs are sized at 4mm. There are no adapters that came with them, like their other larger props have. The instructions state: "For 1/4" shaft; use 9/32" and 5/16" tubing for bushing"... so I take it that it's ok to drill-out the hub and bush-it for a 5-40 using the appropriate size Brass tubing sleeves? I did this to one of them already.. carefully, by using a drill press... but if there's something different I should be doing.. I want to know.

I am also wondering what engine/motor with a 1/4" shaft... would use a prop this small... for APC to recommend this?

Roddie

Roddie,

You can buy a bushing to fit the enlarged hole in the prop. Ken Cook designed them and they are sold on Ebay.

Here is a picture I posted yesterday on another topic, but it shows what they look like.
The fuel tubing works as well though.

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**RknRusty** Mon Jan 13, 2014 9:32 pm

No engine with a 1/4" shaft would use that prop, maybe it was one size fits all instructions in the pack. The rear hole is the one that's properly centered, so don't change anything about it. Just stuff a short piece of medium fuel tube in it that will keep the 5-40 screw centered. The front hole is not good for any alignment purposes. I've only seen e-props with spacers and never received any with IC props. The brass spacer is convenient but not necessary.

Rusty

roddie Mon Jan 13, 2014 9:43 pm

Thanks; Jim, Ron and Rusty. I now recall a thread a week or so ago... where Ken mentioned those bushings. It totally slipped my mind. No one mentioned there being anything wrong with the way I bushed mine... unless it's better to use a reamer than a drill. I just don't want to weaken the prop-hub or create an out-of-balance condition. I've bushed hubs plenty of times... but never enlarged the hole to do so. This is my first experience with a metric size (4mm) hole.

Thanks again guys,
Roddie

ebeneezer Tue Jan 14, 2014 11:31 am

Hi guys, I thought you might like to see how my baby is progressing. I think it may wamt to tip over on take off though. The undercarriage go do with moving forward a tad. As you can see from the the photo, I had a bit of carbon tube looking for a home so I've used it to stiffen the fuz. Just got build an engine now. Anybody know where I can get some 30% nitro fuel here in the U.K.

Cheers Mike Flying

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roddie Tue Jan 14, 2014 2:53 pm

ebeneezer wrote:Hi guys, I thought you might like to see how my baby is progressing. I think it may wamt to tip over on take off though. The undercarriage go do with moving forward a tad. As you can see from the the photo, I had a bit of carbon tube looking for a home so I've used it to stiffen the fuz. Just got build an engine now. Anybody know where I can get some 30% nitro fuel here in the U.K.

Cheers Mike

WOW!!! Ever since I first saw your avatar photo, I've liked that design! Looks radical!!! With that V-tail; I wonder if "full-up" elevator on take off would be enough to keep the tail planted? You're not the only one of us who's concerned about that, with these models!

Try doing a search for motorcycle racing shops to obtain some Nitro. You may get lucky... if someone has some; they may give you a pint... and you can then blend a 30% mixture into whatever glow-fuel is available over there.

Roddie

ian1954 Tue Jan 14, 2014 3:59 pm

http://www.southernmodelcraft.co.uk/model-fuels.php

These people will make up fuel for you but not deliver - you have to collect.

I can't find any place that will deliver and can supply 30% nitro.

It is even difficult to find anyone who will deliver castor oil lubricated fuel.

http://www.ebay.co.uk/itm/Modelsport-UK-Professional-25-Glow-Fuel-1-litre-MSP253-/370947529242?pt=UK_ToysGames_RadioControlled_JN&hash=item565e321a1a

ebeneezer Tue Jan 14, 2014 4:44 pm

Thanks Roddie, full up might do it. You can tell I'm more of a builder and less of a flyer. As for the fuel, thanks Ian southern model craft should do it.

Cheers Mike Flying

GUS THE I.A. Tue Jan 14, 2014 5:24 pm

Here is a picture of the A-7 Corsair II, that I built for the speed contest. It will surely need some tweaking to get the best from it, but I think it captures the look of the original, enough to compete.

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**Cribbs74** Tue Jan 14, 2014 5:30 pm

Holy crap Doug!!!!

That is some level of detail!

Good job man!

roddie Tue Jan 14, 2014 5:40 pm

GUS THE I.A. wrote:Here is a picture of the A-7 Corsair II, that I built for the speed contest. It will surely need some tweaking to get the best from it, but I think it captures the look of the original, enough to compete.

Ah.. the first trike-gear I've seen so far.. and a sprung nose-gear!!! Super nice Gus!!!! Is your lead-out guide set in a tube? That would provide for some great adjustability with that swept wing.

Nice job Gus!
Roddie

GUS THE I.A. Tue Jan 14, 2014 6:18 pm

Thanks guys! I'm sure the leadouts will need moved, but they aren't adjustable, yet.

You know... I still have the Bonanza going. I've flown it. It's a trike, too. I guess I have not put a shot of it on here. Hang loose. It's painted red, and checkerboards on it.

GUS THE I.A. Tue Jan 14, 2014 6:46 pm

Ah... The Bonanza! It is a little rough. Hand-painted, and I haven't put the "N" number on it, yet. But, it flew. Broke the prop and tail when I "landed" it, but, ready for more testing. I have a feeling- it will be a matter of the best engine, that claims the prize. My builds are overshadowed by the craftmanship that the other guys planes have. Theirs are cool and precise. Mine are cut and glued.

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BUT HEY! RED AND BLUE MAKE PURPLE!!!!!

pkrankow Tue Jan 14, 2014 7:12 pm

roddie wrote:
GUS THE I.A. wrote:Here is a picture of the A-7 Corsair II, that I built for the speed contest. It will surely need some tweaking to get the best from it, but I think it captures the look of the original, enough to compete.

Ah.. the first trike-gear I've seen so far.. and a sprung nose-gear!!! Super nice Gus!!!! Is your lead-out guide set in a tube? That would provide for some great adjustability with that swept wing.

Nice job Gus!
Roddie

I didn't think this was being played in that league. Wow. That is nice.

Phil
PS I don't stand a chance against that in a photo contest.

roddie Tue Jan 14, 2014 7:20 pm

GUS THE I.A. wrote:Ah... The Bonanza! It is a little rough. Hand-painted, and I haven't put the "N" number on it, yet. But, it flew. Broke the prop and tail when I "landed" it, but, ready for more testing. I have a feeling- it will be a matter of the best engine, that claims the prize. My builds are overshadowed by the craftmanship that the other guys planes have. Theirs are cool and precise. Mine are cut and glued. BUT HEY! RED AND BLUE MAKE PURPLE!!!!!

Gus, That Bonanza's so cool!! When I see someone else's airplane... I always see a sense of pride beyond all else. Where we're doing this as a group... it makes it all that much more special!

Roddie

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CEF speed contest Design Discussions