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July-2019
Mike1484's

"Tee Dee .020 on a free-flight model"



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Post  dirk gently on Sun Jul 14, 2019 10:05 am

Here are some pictures and a flight video of my electric Curtiss Hawk 75 that I built quite some time ago.
It flies fine, but it's somewhat boring, so I am converting it to nitro power. I am just waiting for the fuelproofer to dry, and all that's left to do is bolt the engine on.

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Why is it potentially a terrible idea? Well, the model, with its 24' wingspan is quite a bit smaller than what I would normally put a Baby Bee on. Wit a 5x5' prop it will be a rocket. Regardless of whether I fly it successfully or crash it, I promise I'll share a video with you guys  Very Happy
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Post  Kim on Sun Jul 14, 2019 12:41 pm

Positive Mojo to you !!!!!!!!!!!!!!!!!!!!! RC Plane
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Post  Marleysky on Sun Jul 14, 2019 3:01 pm

Great looking plane, fun to fly, super video! Thanks for sharing with us!
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Post  KariFS on Sun Jul 14, 2019 4:56 pm

Again a great looking model, and again of a plane type that the Finnish Air Force used in WWII.

A Babe Bee will bee quite powerful and heavy for that model. Quillow’s models of the same size have instructions for installing a Pee Wee, and they recommend installing the propeller backwards to reduce the thrust. Of course those are free flight models originally designed for rubber power so they are not as robust as your Curtiss seems to be.

Good luck with the flight, looking forward to seeing the video Thumbs Up

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Post  batjac on Sun Jul 14, 2019 5:03 pm

Oooooohhhhh! I just LOVE terrible ideas! And I also love the P-36. Got wings and a four stoke engine waiting for me to make up a P-36 fuselage.

The Hawkish Mark
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Post  akjgardner on Sun Jul 14, 2019 6:27 pm

KariFS wrote:Again a great looking model, and again of a plane type that the Finnish Air Force used in WWII.

A Babe Bee will bee quite powerful and heavy for that model. Quillow’s models of the same size have instructions for installing a Pee Wee, and they recommend installing the propeller backwards to reduce the thrust. Of course those are free flight models originally designed for rubber power so they are not as robust as your Curtiss seems to be.

Good luck with the flight, looking forward to seeing the video Thumbs Up

I have flown several 400 series airplanes with babe bees, they are fast but mine all flew well.
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Post  KariFS on Mon Jul 15, 2019 3:03 am

That’s good news ajkgardner, have you flown them R/C too? I have never seen the 400 series plans, I was thinking of the 300 series (24” private planes).
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Post  dirk gently on Mon Jul 15, 2019 3:58 am

KariFS wrote:Quillow’s models of the same size have instructions for installing a Pee Wee, and they recommend installing the propeller backwards to reduce the thrust.

This model is nearly 200g, so a Pee Wee just wouldn't pull it. It came out slightly lighter with the Cox engine than with electric power, although not by much. On the other hand, the Baby Bee will be waaay more powerful than the puny electric was. It looks quite at home, so I'm beginning to feel optimistic. Another positive is that I have pretty good access to the needle valve and I didn't even have to cut out half of the cowling.

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Post  Cribbs74 on Mon Jul 15, 2019 9:52 am

Going from electric to glow is never a bad idea Laughing

I wonder if a TD .020 would have been a better fit? They are pretty powerful for their size. Hope to see it fly!
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Post  dirk gently on Mon Jul 15, 2019 9:58 am

Cribbs74 wrote:
I wonder if a TD .020 would have been a better fit?

Possibly, if I had one. They seem to be unobtainium, at least where I live. I have never even seen one put up for sale online, let alone with my own eyes. On the other hand, the model barely balances as it is, so having a heavier engine doesn't seem like a bad idea.

I'm planning on flying the model this Thursday.
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Post  roddie on Mon Jul 15, 2019 7:19 pm

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Good Luck D.G.!!! That Babe Bee looks right-nice and proud...  Babe Bee .049   up-front there! Maybe make a needle-adjusting tool, using a short piece of automotive vacuum hose (rubber type).

The "knob" on your engine's needle looks like the smaller (later) type. A piece of 3/16" (.187") inside-diameter hose would be a good fit. The early Babe Bee's had a larger-diameter knob on their needle.. and would require 1/4" (.250") inside-diameter hose.

The hose; you'll probably have to purchase by the "foot".. unless you happen to have some. You'll only need an inch or two of length to reach down through the opening in the top of your cowling.. but it will be MUCH easier than trying to get your fingers in there.
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Post  akjgardner on Mon Jul 15, 2019 7:51 pm

KariFS wrote:That’s good news ajkgardner, have you flown them R/C too? I have never seen the 400 series plans, I was thinking of the 300 series (24” private planes).
yes , they fly pretty nice, they fly better with a wing mod. Semi symmetrical wing instead of the flat bottom wing that comes with the kit
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Post  dirk gently on Tue Jul 16, 2019 3:07 am

roddie wrote:Maybe make a needle-adjusting tool, using a short piece of automotive vacuum hose (rubber type).

The "knob" on your engine's needle looks like the smaller (later) type. A piece of 3/16" (.187") inside-diameter hose would be a good fit. The early Babe Bee's had a larger-diameter knob on their needle.. and would require 1/4" (.250") inside-diameter hose.

The hose; you'll probably have to purchase by the "foot".. unless you happen to have some. You'll only need an inch or two of length to reach down through the opening in the top of your cowling.. but it will be MUCH easier than trying to get your fingers in there.

Thank you for the advice, I've been looking for a way to make the needle longer and I haven't been able to come up with anything that wouldn't permanently alter the factory needle, which I don't want to do. I will definitely give the vacuum hose idea a try - in a different model - in this one the access to the "knob" is surprisingly comfortable.
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Post  Surfer_kris on Tue Jul 16, 2019 3:35 am

The hose material is not critical and if it hardens with time it almost works better (it stays in place and doesn't flex) compared to a soft and fuel-proof material.

Here is one examples that I used in the 80-ties (PVC line for a fish tank):
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Post  dirk gently on Tue Jul 16, 2019 3:44 am

Wow, that engine looks like a moonshine distillation facility Laughing
What's all that stuff that's attached to it? Is the needle valve actually servo-controlled?
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Post  Surfer_kris on Tue Jul 16, 2019 5:20 am

That's my very first glow engine, sporting a DIY muffler, custom sealed tank (due fabrication error) and routing for an external tank. I think it was also the engine of the month a few years back. Smile
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Post  getback on Tue Jul 16, 2019 4:30 pm

That's a Fine looking airplane there and i hope she will perform for you! RC Plane Let me go back and finish the Vid now / Very Happy
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Post  Mark Diedrichs on Tue Jul 16, 2019 4:54 pm

Rube Goldberg would be proud!! Very innovative idea!!! Wow beyond cool, Mark
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Post  dirk gently on Thu Jul 18, 2019 2:03 pm

The maiden flight today didn't go exactly to plan.

The last time I actually ran this engine was when the horizontal stab on my Dewoitine decided to wander off mid-flight and I crashed the model nose-first into the ground. The airframe was written off, and the engine was full of dirt and sand, so I disassembled it and washed it with acetone to make sure no sand could damage the piston or cylinder. I never actually ran the engine after that crash, I just assumed it was OK and put it on the Curtiss.

However, my assumption as proven wrong when I tried to start it today. It ran rough, was stopping abruptly for no apparent reason, and it never got past 10k RPM. So there is definitely something wrong with the engine. Maybe it's the leftover acetone trapped in the engine, maybe it's sand in the fuel line, or worse yet, the engine is actually broken somehow.

During the weekend I will take it off the model, disassemble it again, clean it thoroughly and bench-test it before using it on the model again.
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