Build Log: Converting a 31" Super Cub to .049 Power (revisited)

I've got a standard Cox 6x3 on it now, as I need power over speed to haul the heavy thing into the air. (too much speed as it is lol)

I switch back and forth between electric and glow. I just lost patience with electric (crash, see S.A.D. soon) so this will get a little more attention soon.

Honestly electric is the way to go.... Cox engines are just FUN

John Goddard wrote:Halllllleeeeeeeeeluuuuuuya
Tell it like it is Brother Jared
The PeeWee in the Bacaruda's got this weekend to shape up or ship out too

This is a'waitin in the wings.......



Plane designed for td010 power as well

I love my COX PeeWee 020`s but they are often referred to as TD020 parts donors when they misbehave beyond my patients limits for a reedie lol

And MFD, dude if the reedie 049 engine is such a big problem pm me man

WingingIt74 wrote:Honestly electric is the way to go.... Cox engines are just FUN

Ouch!!!!!!!

Matt, if you take it off, you can fix the engine and design a way to make it more accessable at the same time.

Don't throw in the towel, it's worth the hassle.

Weird thing I recently found, that may/may not be relevant. Oldish (metal backplate) BW, exhaust throttle, running Sig Champion 25%. Would start easily at first, needle, but after about 25 seconds (long enough to turn on tx/rcvr and get ready to handlaunch) it would just wheeze and die. Starting was a bit reluctant then, and would again die after 25 seconds or so.

Swapped out the glow plug and it ran fine for a short flight or two. Next day it started doing the same thing.

Remembered reading something here about one of the old Cox people periodically cleaning glowplugs with muriatic acid. Took both plugs and siphoned a bit of sulfuric acid out of a mc battery, let it soak the element for a couple minutes, then rinsed them up. After that it ran without a problem.

First plug was newish, came with the BW when I got it off ebay. Second was a fairly old used TD plug. Go figure.

A year or so ago I had a rash of glowplugs failing, after never even having them go bad since I was a kid. I had just started using Sig 25 and 35 and finally blamed it for my problems. They were turning white and frosty too. I could wash them with alcohol and get another bur or two, but they were basically shot. I quit using Sig fuel and the problem went away. I finally gave the rest of it to Microflitedude. I don't know if he had any trouble or not. I started using the 35% again last month and so far no problems.

The engine will run through the whole tank on the ground without a problem.



Nothing odd about the glow plug. The engine is an easy starter, and will start right back up if stopped. (I usually hold the vents) I have used GPB and spiked Traxxas fuels.

Yes, electric is fun, quiet, clean, and convenient. Glow has the extra power, sound, smell, and pain we have all come to love despite everything.

Could a mildly imbalanced prop cause this? Or too large a prop?

(see previous post)

microflitedude wrote: Nothing odd about the glow plug. The engine is an easy starter, and will start right back up if stopped. (I usually hold the vents) I have used GPB and spiked Traxxas fuels.

Yes, electric is fun, quiet, clean, and convenient. Glow has the extra power, sound, smell, and pain we have all come to love despite everything.

I don't know about gas having extra power....

oh, I picked up a used Habu last night

microflitedude wrote:Could a mildly imbalanced prop cause this? Or too large a prop?

(see previous post)

I don't think so.

Nice throttling you have there.

I'm only guessing here, but I think you may have it set too lean i.e. the mixture is set to an optimum on the ground. It will then run fine on the ground but a soon as the plane moves forward the load on the prop gets lower and the engine will, or should, rev up. The higher revs then have a higher need for fuel and thereby it needs a richer setting on the needle. So set it rich enough to stumble a bit on the ground and it may well then be fine in the air as the engine unloads.

You could possibly mimic the unloading in the air by blowing into the prop arc with compressed air. I haven't tried it myself, but someone has to be the first...

Haha, yeah hit it with 200mph air and see what it does. Might back off a bit to get a good test, that should work pretty well. I wish I didn't have to go to the tire store to fill my air tank or I would forge through the sleet and rain and try it now.

I ran it a little rich on the ground, and I think it ran a little better in the air. I'm not sure how hot these are supposed to get, but a drop of fuel on the head will instantly boil off after a 2 minute flight. If the mixture doesn't work, its off with the engine!

I've got a gas leaf blower...

"Funnyfarm? Yes, my young neighbor is blasting a leafblower into an airplane with a tiny screeching engine..."

Ha! Snow! I didn't believe it could happen. I'm glad it did though.

If you are flying in the snow you might be over cooling the engine and the glow plug is going out. For my snow flight experience I have wrapped some yard deep in the cooling fin grooves so the head stays lit since I was having no problem on the ground but the plane would die in the air.

This was control line with no throttle. The risk is overheating the glow head and burning it out. Little or no risk to the engine otherwise.

Phil

PS was the boiling fuel after the engine quit in the air?

Not flying in snow - was in the 60's and sunny.

Yes, after I ran the tank out and landed, I dropped some fuel on the head.

I think your Norvel is going on my FF5 next
Week Matt.
I could always send it back Stateside....

That would bring a whole new meaning to the word "rocket".

Have fun with it!

WingingIt74 wrote:

microflitedude wrote: Nothing odd about the glow plug. The engine is an easy starter, and will start right back up if stopped. (I usually hold the vents) I have used GPB and spiked Traxxas fuels.

Yes, electric is fun, quiet, clean, and convenient. Glow has the extra power, sound, smell, and pain we have all come to love despite everything.

I don't know about gas having extra power....

oh, I picked up a used Habu last night

4 hours, two planes, a swap meet, and $95 later...

New UMX GeeBee and a used Flyzone Select Scale Cessna Corvalis 400.

[quote="Surfer_kris"]Nice throttling you have there.

I'm only guessing here, but I think you may have it set too lean i.e. the mixture is set to an optimum on the ground. It will then run fine on the ground but a soon as the plane moves forward the load on the prop gets lower and the engine will, or should, rev up. The higher revs then have a higher need for fuel and thereby it needs a richer setting on the needle. So set it rich enough to stumble a bit on the ground and it may well then be fine in the air as the engine unloads.

I do believe I had this once or twice myself now that he mentioned it.