Getting Out From Under the Wing?

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Bigshu

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100 hp helicopter will use 10-15 to turn the tail rotor. That is what the driveshaft is sized for.
Yeah, that's what the salesman was telling me. I'm wondering what the shaft size would have to be to handle 65-100hp? Mini-imps just use a regular off the shelf drive shaft of the appropriate length AFAIK. I'm just curious as to how that would work as a practical solution to a pusher with a shaft driven prop of normal size for the application.
 

TFF

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Their are people who can figure it out pretty easy. My eyeball guess is around 2 1/2”

I have spent a lot of time with 200 hp helicopters with 3/4” 4130 driveshafts. They twist pretty easy, and manhandled, it would bend the flex couplers without too much crazy work.

Helicopters work at a vary narrow rpm range, so they are not changing rpm with throttle to fly. Torsion from throttle changes is not high like a propeller.
 

D Hillberg

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Their are people who can figure it out pretty easy. My eyeball guess is around 2 1/2”

I have spent a lot of time with 200 hp helicopters with 3/4” 4130 driveshafts. They twist pretty easy, and manhandled, it would bend the flex couplers without too much crazy work.

Helicopters work at a vary narrow rpm range, so they are not changing rpm with throttle to fly. Torsion from throttle changes is not high like a propeller.
What helicopter?
Enstrom has a 4130 steel tube 1/2 inch die .040 wall single piece 4+? hanger bearings
Bell 47 '' '' '' 6+? hanger bearings
Bell OH 58 / 206A has a 1 inch die aluminum tube .043 wall single piece 5+? hanger bearings
Later Bell had segmented t/r shafts with Thomas couplings
Bell UH 1 - 3 inch aluminum tube .030 wall multiple hangers lots of greased couplings
Sikorsky S-58 1.5 die aluminum shaft .050 wall single piece 3 hangar bearings
Hughes 2.5 inch die aluminum tube .030 wall no hanger bearings
R 22 3/4 (?) die steel tube .040 wall one bearing mid span
R 44 1 1/4 aluminum tube .060 wall one mid span bearing

Jet Exec had 1 inch .040 wall aluminum tube one piece
Mini 500 ?
Helicycle ?
 

D Hillberg

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Enstrom. It might be 5/8. .065 I think. I put on the last one made possibly.
F 28 280 FX are 1/2 inch die - used to overhaul them - Had one scoop the shaft & hangers off the entire tail boom by a blade after a bumped landing - From flex pack to flex pack - one big loop of drive shaft.

the bearings inner race had a big grommet you slid the shaft through , taper pin reamed to fit on the ends,
Don't know what they use on the later Enstroms. I do like their 480 turbine setup
 
Last edited:

TFF

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When I’m back to the last aircraft I will measure it. Have 3 or 4 broken ones lying around also. Not until about year 2000 did they do any precision straightening of the shafts. What is funny is I can’t answer the turbine question. I think it’s the same. Couplers are six bolt instead of four. I worked on them both every day for fifteen years, and last year we closed shop. I only see one every month or two right now.
 

D Hillberg

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When I’m back to the last aircraft I will measure it. Have 3 or 4 broken ones lying around also. Not until about year 2000 did they do any precision straightening of the shafts. What is funny is I can’t answer the turbine question. I think it’s the same. Couplers are six bolt instead of four. I worked on them both every day for fifteen years, and last year we closed shop. I only see one every month or two right now.
I took a Bell 47 t/r shaft coupler and anskyshark-helicopter.jpgIMG_0014.JPGIMG_0017.JPG10842d1297467860t-what-do-you-think-picture-392.jpgan EnstIMG_0014.JPGIMG_0017.JPG10843d1297467867t-what-do-you-think-papa-2-003.jpg10842d1297467860t-what-do-you-think-picture-392.jpgskyshark-helicopter.jpgrom drive flange and slid them on an Enstrom t/r gearbox
on a toy I'm building and all connected to a Hughes Drive shaft to a Bell Long Ranger oil cooler fan shaft
to a R-22 sprag clutch connected to a Gold Wing motorcycle final drive
To a Rotorway Scorpion mast topped with a S-58 T/R hub and grips
Finished with four R-22 blades

Edit: What a mess.... Posting that is
 

TFF

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What no Hillers? Don’t think it will work without Hiller parts. It’s a lot of work. Especially the multiple blade head.
 

Bill-Higdon

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I took a Bell 47 t/r shaft coupler and anView attachment 120376View attachment 120372View attachment 120373View attachment 120375an EnstView attachment 120372View attachment 120373View attachment 120374View attachment 120375View attachment 120376rom drive flange and slid them on an Enstrom t/r gearbox
on a toy I'm building and all connected to a Hughes Drive shaft to a Bell Long Ranger oil cooler fan shaft
to a R-22 sprag clutch connected to a Gold Wing motorcycle final drive
To a Rotorway Scorpion mast topped with a S-58 T/R hub and grips
Finished with four R-22 blades

Edit: What a mess.... Posting that is
Kind of like Johnny Cash's Cadillac in one piece at a time
 
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