Fun with Generic, Non-Threatening Title

batjac Fri Jul 15, 2016 4:43 pm

Roddie’s post on the Golden Bee thread reminded me that I had put this aside for later until I could re-work the power pod the engine is in. The engine runs fine, but I found that the hard tank I used didn’t give a good engine run, so I figured I’d make some time eventually to do a balloon tank. Besides, I’d been using a wing from another plane to fly the new plane. So, last night I modified the mounting pod for a balloon tank and made up a new wing from some scrap coroplast.

With the balloon tank, the pipe bomb was running at right around 17K on the 5x3 rubber ducky, so I took the plane out this morning for a quick test. Also, it gave me a chance to finally test out my hatcam I made a couple of months ago. The plane is heavy at 8 ounces dry, and the plane is really only suited to training use, so the included video is mostly just 4 minutes of roundy-roundy with a couple of wing overs. An ounce of fuel gives about 7 minutes on the pipe bomb engine. Not bad. Just under two hours of flying on one quart of fuel.

The video starts in mid-flight because about a minute or so into the flight, I remembered I forgot to turn on my hatcam. So, I had to take off the hat and turn on the hat cam one-handed while trying to keep the plane flying level. It didn’t help that I couldn’t remember which button to push and the buttons were all matte black with recessed symbols on them. It wasn’t immediately obvious which buttons did what.

The field I flew at is obviously not very good for a hatcam, as there are so many trees flying by in the background that it’s kinda distracting. But at least the plane is pretty well centered in the video. Using my handy dandy circular slide rule I made up, I calculated the plane is flying a blistering 35 MPH on the 5x3 prop and the 33’ lines I have on the handle. The wind was picking up towards the end of the flight, so I settled for just the one flight as proof that the mounting pod works.

Now, I figured I’ve proven that the pipe bombs can be flown on a simple to make mount, so Phase II is to make some planes specifically for the pipe bomb that will give decent performance. I skipped from the BTC-2 line to the BTC-4 line, so maybe I’ll backfill the BTC-3 line for using Testors/Wen-Mac engines.

The Transitioning Mark

Oldenginerod Fri Jul 15, 2016 6:42 pm

Well done. Proof that you can make use of a pipe bomb if you put your mind to it. Although, it seems that the engines didn't like to be loaded up. Every time you climbed it seemd to really die off. Maybe a little lean?

**RknRusty** Sat Jul 16, 2016 12:11 am

Hey that flies better than it ever could have in the original plastic models they came with. Good work. And yeah, just a little lean or it would have sped up tight before it cut off. This is a good thread, and the first time I've ever read the whole thing. I'm surprised at its performance. It sounds just like a Cox...type engine. Lol

Marleysky wrote:Here is a dis-assembly of a Testors P51. I call it the One Screw Wonder, because it is held together by only one screw!! Not anywhere near the complexity of a Cox Stutka. Remove just one screw from the bottom, gently lift the plastic belly pan up and away from the fuse. take a long thin pry bar ( kitchen knife i=or screwdriver) and pry up on the locating pins on the port and starboard wings. Pop them free and continue to twist the belly pan back and forth while pulling back untill the motor pops free of the front cowl. BINGO totally dis assembled. the one piece landing gear assembly is held in place by the single screw that hold the top and bottom together, while the bell crank is held in position on a plastic shaft or pin between the top and bottom. SO easy...even a caveman could do it!!

Nice looking P-51. Bob Zambelli designed a stunter with a one screw take-apart system. Pull that one pin and the whole plane drops its wings, power pod and empennage. It's amazing how it just falls apart on the table.

Marleysky wrote:...Sat it down( unrestrained ) on the workbench (stooge) and as I was reaching for the camera, she leaned out screaming a DRAMIATIC increase of RPMs and flew off the work bench about 6-8 ft ran out of gas and landed in the weeds!! IT Runs it Flys, but I don't think with the small tank size that it would last two or three minutes in the air.

That's hilarious

1/2A Nut Sat Jul 16, 2016 3:17 am

Really steady runner well done. Cool

Unloaded rpm some of the readings

18,410 (mostly here 52 mph potential)
18,491
18,572
18,733 (53.22 mph)

batjac Sun Jul 17, 2016 7:32 pm

Rod and Rusty. The needle was set to get a consistent 2-cycle run. The needle on that engine only has 3/4 turn between 4-cycle and too lean to run. The engine was set to a reliable 2-cycle without dropping off in either direction. I'm wanting to chuck the needle in a drill and do a little re-profiling of the needle, but I don't want to mess it up and get a needle that won't work at all. This weekend I'm going to try different pipe bomb needles to see if there's one particular needle that works better than others. I might even pull a couple of needles from some unused Wen-Macs to see if they'll fit and idle better.

The Mix-N-Match Mark

batjac Mon Jul 18, 2016 1:02 am

I didn't post a picture of my hacked and modified engine pod. Here 'tis. The capped fill tube goes up through a hole in the top of the fuselage. It's kinda long so that it's easy for me to pinch off and plug in the fuel syringe. I elongated the fuel tank platform and placed a firewall at the back to keep the balloon in place.

Fun with Generic, Non-Threatening Title - Page 3 DSCN4575_zpsrfitqiis

Fun with Generic, Non-Threatening Title - Page 3 DSCN4575_zpsrfitqiis

The Slasher Mark

**RknRusty** Mon Jul 18, 2016 3:41 am

That's a really nice piece of hardware you've built.

roddie Mon Jul 18, 2016 5:38 am

Good going Mark! Thumbs Up

I think that's the first vid I've seen with a balloon tank being used for control-line. I suspect you're using a 9" round-size party balloon? I have a few different sizes/shapes to try eventually. You may want to try a 6" round if you build another mount. I remember you modified a heli-backplate for the Cox Pee-Wee .020 which would make a really interesting set-up for a small 14-16" span airplane for 20-25' lines.

This is your photo of that Pee-Wee mount.. correct?

Fun with Generic, Non-Threatening Title - Page 3 Cox_sk10

Fun with Generic, Non-Threatening Title - Page 3 Cox_sk10

Are the NVA's the same between the Cox .020/.049 product backplates? I'm curious whether a Cox NVA could be installed in the Testors engine? Might be something to try for a wider range of adjustment?

batjac Mon Jul 18, 2016 11:27 am

RknRusty wrote:That's a really nice piece of hardware you've built.

Thanks for the compliment, Rusty. It's more of a hack it together thing than a pre-planned thing, so I can't claim any wisdom or ingenuity on this one... It just all came together.

The Slap-Dash Mark

batjac Mon Jul 18, 2016 12:12 pm

roddie wrote:I remember you modified a heli-backplate for the Cox Pee-Wee .020 which would make a really interesting set-up for a small 14-16" span airplane for 20-25' lines.

This is your photo of that Pee-Wee mount.. correct?

Are the NVA's the same between the Cox .020/.049 product backplates? I'm curious whether a Cox NVA could be installed in the Testors engine? Might be something to try for a wider range of adjustment?

Roddie, I've seen that picture before, but that's not mine. My mod makes the backplate so that it has mounting holes that fit the normal tanked PeeWee hole pattern. I flatter myself that my mod is cleaner and more pleasing to the eye.

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Fun with Generic, Non-Threatening Title - Page 3 DSCN1647_zpsf56df2ea

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I've put a Cox needle valve assembly in a Wen-Mac, so the needle should work fine in a Testors engine. In fact, I did consider putting in a Cox needle assembly to see what that'd do. I just decided I didn't want to try to push out the spraybar from the Testors backplate and possibly screw it up, since there's not that much meat left to the plastic after cutting it down from the original configuration. Besides, my original ultimate goal was to make a plane that would use the stock pipe bomb engine that someone would throw out otherwise.

Yes, I used a 9" party balloon. A 6" one would probably work as well or better, but the only bag of balloons at the store that was specifically marked for helium was for 9" balloons. I now have a bag of about 20 9" balloons to use up first.

The Pleasant Mark

getback Tue Jul 19, 2016 12:40 pm

My question is why is the grass brown is it winter there ? Nice going on the set up looks good and works well , your right as cheap as the engines are they should be utilized and didn't sound bad neither , flew well on a 8oz. plane I think but did land like a rolling rock Beer Cheers

Good Fun !! Eric Thumbs Up

Oldenginerod Tue Jul 19, 2016 5:26 pm

getback wrote:My question is why is the grass brown is it winter there ?

What country are you in Eric?

roddie Wed Jul 20, 2016 7:29 pm

getback wrote: Nice going on the set up looks good and works well , your right as cheap as the engines are they should be utilized and didn't sound bad neither , flew well on a 8oz. plane I think but did land like a rolling rock Good Fun !! Eric

Yea.. I agree on the engine-run. Sounded a bit lean.. which has been discussed, but Mark might be able to work some magic with the stock NVA. I "get it".. his wanting to utilize this engine in "bone-stock" form.. aside from a workable mount. No sense in complicating matters the way "I" usually do. Rolling Eyes

Regarding the landing.. I believe that Mark shares my perspective on putting landing gear on little airplanes. You can't beat the way it looks. How many aircraft have you seen (un-scathed..) sitting on the tarmac/field on their belly? Maybe it's a scale-thing with me; but landing-gear just seems to make a model airplane look more like the real thing in miniature. Granted if used; a music-wire gear is best positioned just behind the engine-mounting. Many 1/2A kits with gear, have the gear-legs positioned far-forward for the best chance of a "greased-landing" on a hard-pack surface. Shocked

Grass is less forgiving with little wheels. 1" diameter wheels won't roll.. on even the shortest-cut grass. I think it's worth it to make-up some larger-diameter (1-3/4" to 2") auxiliary wheel-sets to try. Make them from thin/lightweight material. They're easy to make. Use a compass to draw the diameter.. and the center-point serves as the pilot for drilling the axle-bearing; a short piece of alloy tubing CA-glued into place. Wheels could be made of 1/8" balsa treated with thin CA-glue, for rigidity. They may only last a few flights.. but look at them as sacrificial parts that could help to save on broken high-performance rigid-plastic propellers.

getback Thu Jul 21, 2016 8:45 am

Oldenginerod wrote:
getback wrote:My question is why is the grass brown is it winter there ?

What country are you in Eric?

I am in the good old USA the land of the Green this time of year Fun with Generic, Non-Threatening Title - Page 3 01510

Eric

Oldenginerod Fri Jul 22, 2016 6:29 am

getback wrote:
Oldenginerod wrote:
getback wrote:My question is why is the grass brown is it winter there ?

What country are you in Eric?
I am in the good old USA the land of the Green this time of year Eric

Yes Eric I know that. I was being sarcastic, because even this dumb Aussie Australia

knows that if it's summer in one part of the USA then it's summer all over the USA, even in Portland where Mark is.
I guess I'm just familiar with green meaning winter and brown meaning summer Hot

down here.

Rod.

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