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Shed Machinist
02-27-2005, 05:48 PM
I have been working in my shop since about eleven this morning. I am usually up and ready to go to whatever i plan to accomplish by 7, but i decided to clean my room. (it makes my mom happy) After cleaning my room i went out to my shop, and began to work on my belt sander. My friend, and also shop buddy,helper arrived about 11:30 and planned to help me tote around tools back and forth from my shop to outside.
He got around to asking me if i would build him a piece so he could start his model ariplane engine. I told him to buy one, and he said they were about $50 around here, and he couldn't come up with the necessary funds (normal conversation between 14 year olds around here). After 3 hours of him whining i decided i would build it for him. We agreed upon my plan as it was a lot more feasible.

I found a 1.5" length of .5 hex stock, a 3" piece of 3/4" black pipe, and a 3" piece of 1" black pipe to build this. I sized the piece of 3/4" down by cutting 4 slots with my grinder and then beating them in with a hammer. I did the same with the 1" but bent the tabs outward. i welded the hex stock to the smaller end of the 3/4" and then slid the larger end in the smaller end of the 1" pipe. after welding this altogether and welding over the slots on the 3/4" completely, and welding about halfway up the 1" 's slots. i ended up with a "Rockety Looking Engine Starty Thingy" That is the most confusiong explanation ever, i know.

My friend and i have tested in a drill motor, and it spins farely balanced. I am going to post pictures here... http://www.freewebs.com/shedmachinist/

I painted it with 2 coats of red primer and 2 coats of some chrome i accidentally came across today To make it Real Purty.

[This message has been edited by Shed Machinist (edited 02-27-2005).]

Paul Gauthier
02-27-2005, 06:59 PM
Shed.
Don't see no pics at your site. Looks like it might be cool though when you get them there.
I never fooled around with rocket motors when I was a kid. (and that is farther back than I want to think about.) but I know that they require some type of propellant. Do BE CAREFULL. Keep track of you fingers and toes and eyballs etc.

------------------
Paul G.

[This message has been edited by Paul Gauthier (edited 02-27-2005).]

Mike Burdick
02-27-2005, 07:13 PM
Can't see any pictures either.

[This message has been edited by Mike Burdick (edited 02-28-2005).]

mattc
02-27-2005, 07:17 PM
not knowing a lot about model air planes, does the bent fingers on the end of the 1" pipe slide over the prop blades and spin them with a drill? if so how do you keep the prop from hitting when the engine fires?

Matt in AK

Shed Machinist
02-27-2005, 07:50 PM
I apologize, i should have been more clear, if you would see the pictures, you would understand.
I have been having troubles with getting pictures, but they will be ther within a few days. Because of how it was built it resemples a rocket, but it is just a cone that slips over the cone of the propeller.
It slides over it, but stops before it gets to the blades. Once i am finished i will epoxy some type rubber to the inside for a better grip.

andy_b
02-27-2005, 09:00 PM
shed,

do you mean a cone starter? if so, yeah, a decent one at a local shop probably is $50.

http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXL396&P=ML

andy b.

Shed Machinist
02-28-2005, 06:41 AM
That would be it andy, except for mine is only an attachment for a power drill.

torker
02-28-2005, 07:52 AM
Shed, you can get the soft rubber cone inserts for a few bucks. They wear out so are widely available. You almost need the real thing or something like it. It's soft enough to grap the nose cone hard enough to turn the motor.

uncrichie
02-28-2005, 01:00 PM
If his plan is to use a cordless drill as the starter for the cone adapter it probably won't work. Been there, it won't spin fast enough and depending on the drill it may not even have enough torque. Good luck though. Uncrichie...

ricksplace
02-28-2005, 02:59 PM
Hi Shed.
My son has a gas powered remote control car. The starter thingy runs off 12 volts and has a rubber thingy on it that rubs on a knurled wheel connected to the crankshaft of the motor. The rubber thingy on the starter has a tapered hole in it for just such an application as you mention. It should be available at a hobby store for less than $10. No reason a good cordless drill shouldn't spin it fast enough to start a model airplane engine. You'd just need to make a mandrel of some sort to mount the rubber thingy on.

Rick

Shed Machinist
03-01-2005, 06:58 AM
I finally have pictures at www.freewebs.com/shedmachinist (http://www.freewebs.com/shedmachinist)

The plan is to hook it up to a corded drill, it runs with variable speed up to about 1200 rpm (supposedly) but runs a little slower with the attachment in it, so probably about 1000+.

It should easily have enough torque, and i know it will grip it, because we already tried with bare metal.

pgmrdan
03-01-2005, 07:42 AM
Looks good, Shed! I've never used one but it looks like it should work great.

Paul Alciatore
03-01-2005, 07:58 PM
I was able to see the pixs and it looks neat. I hope it works.

In my day with model airplane engines, we flipped them with our fingers. Quickly, of course.

Many times had a prop cut on that finger. Sometimes a back flip worked better. Less danger of getting hit.

I had it worked out to fly U-control alone. Start the engine, pin through the tail skid and run to the center of the circle and pull the pin with a cord. Great fun. Better with a friend but I liked to fly whenever I could. Besides, no witnesses to the crashes. Never got around to (or the funds for) RC. Perhaps someday when I have the time and money at the same time.

I can personally attest to the control problems with flying wings. I designed and built a couple and they crashed well.

Paul A.

IOWOLF
03-01-2005, 08:10 PM
Congrats shed mo, You have reinvented the engine starter.cheaper also.

charlie coghill
03-01-2005, 08:43 PM
Shed that is pretty darn good. Keep it up.

snowman
03-01-2005, 08:50 PM
I could never get mine started with a drill...didn't spin fast enough.

My old engine had a little hex hed nut on it.

-jacob

Les Burg
03-01-2005, 08:57 PM
Nice going Shed, keep up the good work.
Les

darryl
03-01-2005, 10:37 PM
Nice. You mentioned epoxying a rubber insert or something to the inside for grip- you could always just 'paint' something on the inside, like shoo-goo, or tool handle coating. Maybe even glue a fat o-ring in there.