Hell's Belle's hell

pilotescort

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The infamous Hell's Belle has her own hell that should be brought to light. No machine is without need of inspection and maintenence. The first problem I've encountered is slow prerotational speed due to a redrive change from 2.62 to 3.47/1. I corrected this by changing my rubber wheel from 4" to 3", and replaced my 7" drum with an 8 1/8" drum. Test results will follow after I reassemble the rotor head from the next problem.
With a relatively heavy machine (760 lbs.) on a single bearing rotor head, hard yanking and banking tears things up quick. In 8 hrs. I managed to CRACK THE REAR LATERAL PIVOT BOLT TOWER, AND BEND BOTH THE FORE / AFT PIVOT BOLT, AND LATERAL PIVOT BOLT. This was immediately realized with a major reduction in RRPM when the blades were not highly loaded.

This damage was also enhanced by a blade flap in high wind from low prerotational speed. It appears any RRPM under 200 is critical and suseptiple (sp?) to flap, especially in high wind (15+mph). In my case, the flap only allowed the hub bar bolts to smash the bendix driveshaft which violently shook the whole rotor head. This I corrected by adding stop-bolts to the hub bar stop plate so at least the hub bar bolts clear the bendix drive.

Jake made me new lateral and fore/aft towers that are NOT bolt bearing, and another machinist cut me a drum while I refitted the 3" rubber wheel. I strongly recommend Jake's design, and not pushing limits too far too long....lol. The rotor you lose could be your own!!!
 

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pilotescort

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Fore/aft block

Fore/aft block

I apologise for the distortion of the pic showing the cracked tower; there's circle around an arrow pointing to a highly visible crack. It's presence surprised even Jake who had never seen that in his l o n g gyro history. The new fore/aft block he made is out of a single piece with bushings going into the torque tube, and bushing from the lateral towers going into the fore/aft block. The bolts now merely hold the assembly together with no chance of over-tightening. This is truly an inspirational work of art, and a thousand times safer. Thank you Jake.
 

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JRB549

J.R. Brown
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.....and flew it from Seabring in a 25 mph headwind like that, 20ish miles. BALLS MAN BALLS.
 

pilotescort

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Just FYI, the changes you have made were implemented by AirCommand years ago, you have been flying a heavy machine on old spec parts..
This is absolutely correct, as what I had WAS AirCommand although of old style. Jake also attributed the crack to metal fatigue under stress. If this rotor head would have been magna-fluxed when I got it the crack probably would have been detected then. It's a good lesson about the reality of used parts.

Mike, I'll see you the 19th.....via trailer and plenty of fuel.....lol.
 

gyroplanes

FAA DAR Gyropilot
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Basically, you took an old Air Command head and turned it into an old Bensen Head :)

Just an FYI. Magnaflux won't work on aluminum. You can buy an inexpensive dye penetrant test kit (made by the Magna Flux company (and others) which works on MOST materials. Look for Dye tell, Spot check and others.
I found a micro crack in a Mitsubishi MU-2 tip tank attachment fitting. If the crack had progressed it would have likely caused the loss of the tank and aircraft. It is a Mitsi service bulletin or AD (it's been a while)
 

pilotescort

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Basically, you took an old Air Command head and turned it into an old Bensen Head :)

Just an FYI. Magnaflux won't work on aluminum. You can buy an inexpensive dye penetrant test kit (made by the Magna Flux company (and others) which works on MOST materials. Look for Dye tell, Spot check and others. I found a micro crack in a Mitsubishi MU-2 tip tank attachment fitting. If the crack had progressed it would have likely caused the loss of the tank and aircraft. It is a Mitsi service bulletin or AD (it's been a while)
Excellent info Tom, thank you very much. I certainly didn't know this, and will pick some "dye penetrant" for my next annual. Could be something everybody should do for an annual rotorhead inspection.
 

Alan_Cheatham

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Dye penetrant is cool stuff and can detect cracks that are hard to see without magnification, it can be a real "eye opener" when you find a crack in a critical part.

.
 

Joe Pires

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PHEW!!!! thats scary stuff. Glad your tellin us about it and us not reading it somewhere else.
 

pilotescort

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Dye penetrant is cool stuff and can detect cracks that are hard to see without magnification, it can be a real "eye opener" when you find a crack in a critical part.
All oddities are real eye-openers. Though we all do pretty good pre-flight and post-flight inspections, it's amazing what we don't even consider can become most hazardous. From rudder cables to contol tube lock nuts to battery connections, and everything regarding the rotorhead, vibration is a silent killer.
My new rotorhead assembly is tight and sweet, although the rotor tach now appears to have lost it's articulation.....lol. Like Gilda Radner said, "It's always something." My 4 stroke engine doesn't seem to like the semi-synthetic oil. The switch from standard 5W-30 to SS is causing excessive blow-by, so I'm switching back to standard non-syn. oil.

Prerotational speed is up, but the jury is still out as to whether or not this set-up is going to be the ticket. I'm considering a belt connection like Ernie uses on his Doms. The colder weather we're having here may be a factor.
 

Dirtydog

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pilotescort : Glad to here you got everything worked out.
I was going through mine also just checking things out to. Also switching from a HM-4 to a HM-5 on my control tubes.
 

pilotescort

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pilotescort : Glad to here you got everything worked out.
I was going through mine also just checking things out to. Also switching from a HM-4 to a HM-5 on my control tubes.
Are you referring to the heim joints? It was suggested that I epoxy them in before bolting to take up any slack. They are right tight. Glad to hear you're staying on top of thing Chris.
 

pilotescort

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Bearing failure

Bearing failure

For some odd reason the lower bearing failed in the gear case cover of my redrive. It seems sufficient oil was drained out upon inspection, however it may not have been sufficient after all. This caused the normally power-off prop to NOT windmill while the clutch was not engaged. All 4 bearings were replaced along with seals and gasket, and finally all is well again. There were some minor alignment problems causing some drag somewhere, but after 4 reassemblies everything is working good as new.

The failed bearing was at least 12 years old, being an older "C" drive according to Lockwood. Flight and landing were unaffected, however unaddressed it could have exploded the gearbox which definitely could have been a problem in the air.
 

pilotescort

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Brooke, I was wondering what happened to you, glad you got her fixed. I just got back from a flight myself. Had a blast. You still based at Wauchula?
Hey Mike, still flying Wauchula, and the engine itself keeps purring right along. At 45 hours, the clutch and hub are in great shape, but 65 hours is the threshold to surpass. Glad to hear your machine is still dancing in the sky. Hope your brother is practicing his simulated engine out landings.....word to the wise.....lol.
 

Earthboundmisft

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Brooke my man, you have been quiet lately. You getting any seat time?
'Missfit' has been trouble-free, pushing 160 hours now.
Larry and I have been "annoying the neighbors" and having a ball.
 
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