Tiltrotor Design and Configuration
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- Опубликовано: 22 дек 2024
- A Video showing the creation of a 3d model of a tiltrotor. And a brief overview of the history of tiltrotors starting with the Baynes and Platt-LePage concepts in the 1930's. First flight on the Trancendental 1-G and the XV-3 in the 1950s. And the first production tiltrotors in the 1990's.
I will continue to add to this project in the future. My next step is to import this CAD model into Blender to create a higher quality animation of the mechanical components.
Technical References:
The History of the XV-15 Tilt Rotor Research Aircraft" Maisel, Giulianetti, Dugan, NASA, 2000
"V-22 Propulsion System Design Paper 91-25", Sonneborn, Kaiser, Covington, Wilson, BHTI, Presented at the 7th European Rotorcraft Forum, 9/24-9/27 1991, Belin Germany.
US Patent US-2702168-A, Convertible Aircraft, Platt, 7/7/1950
US Patent US-2230370-A, Aircraft, Baynes, 2/26/1938
US Patent US-6247667-B1, Tiltrotor Aircraft Pylon Conversion System, Fenny et al., 6/19/2001
US 2024/0124134, E VTOL aircraft with tilting propellers and lifting propellers, B German et. al., GTRI, 4/18/2024
US 2024/0253791 A1, Improved Gearboxes for eVTOL aircraft, S Graves, Archer Aviation, 8/1/2024
Excellent video!
Perfect animation👍
Its interesting that your design has two things which Bell absolutely hated about V-22/609 and its why they moved away from them on V-280, tilting engines and a forward sweep on the wing leading edge.
Whittles book points this out also... V-22 requirements drove them to a design they felt wasn't the best use of the technology.
@@bzig4929 Its also interesting to me how HSVTOL solves even further problems from the V-280 like still having a heavy twist in the rotors, as now you can optimize the rotors for vertical flight and then fold then and use the turbofans for forwards flight.
If there's a drive shaft right across the wing then why put the engines in the nacelles, you could have them in the main body.
Is it a weight loading thing, the engines are heavy and having them in the nacelles effectively right at the point of lift takes that stress off the wing?
You could absolutely design it that way. In fact the first tiltrotors has their engines mounted that way.
Reducing the mass at the wingtips would improve low speed, lateral, handling qualities.
One disadvantage of doing that way is that the driveshaft then becomes a critical part. The osprey has had in service drive shaft failures and, while it's an emergency, it's not catastrophic. With the osprey config, the drive shaft only carries load when one engine fails.
Either way, it's a compromise... Both designs are valid.
This is wonderful!
A suggestion, then questions and a comment:
I would really like for you to bias your generized design to be as close as needed to the V-22 so as to be able do accurately demonstrate the gearing issues that are causing the ongoing V-22 safety and grounding issues. Your intended audience for this should be aviation journalists and policymakers.
Do you believe it would be possible to design a tilt rotor that could successfully autorotate without injuring the crew or passengers?
How much more sensitive are these vehicles to inflight CG changes than fixed-wing or rotary-wing aircraft? Like passengers moving around, or cargo shifting unexpectedly.
A Navy helicopter pilot once told me that the biggest problem they had with the Ospreys early on was trying to transition fixed-wing pilots to them, and the problems diminished when they stopped that and insisted Osprey pilots started out with real helicopter flight school. I’m pretty sure I’ve misremembered exactly which branch he flew for, and that’s probably better for him anyway.🤐
I'll consider the V-22 gearbox suggestion. My model has an overrunning clutch... As would any design, but my model uses a single planetary, whereas the osprey has a dual planetary. I hinted at this when I mentioned the larger osprey requires a deeper gear reduction than smaller machines.
The osprey can autorotate... I've always thought Harry Dunn treated the design unfairly. He has a few good points... The autorotation rate of descent is higher than most helicopters, so less survivable, but it definitely can autorotate. The AW609 took the testing of engine out tiltrotors further by testing through the edgewise flow region and by showing a capability to zero the rate of descent.
No one has yet done a touchdown autorotation in a tiltrotor, but, at least in the US, transport category helicopters are not required to demonstrate touchdown autorotation.
I agree with your friends comment about pilots with no helicopter training. CW Lemoine did a really good video on the recent USAF, Japan, osprey mishap. And he discussed that very topic. I find no fault with that crew, but their decision to continue with a degrading gearbox would likely have been different had they been trained differently... With more of a helo pilot mindset. In the end, it was a material failure and their procedures let them down, but it could have been different.
@ excellent response; thanks! In part, my knowledge about the lack of autorotation is confined to a dozen hours googling and perusing comments, with all suggesting it kind of happened, but not close enough for hand grenades, so you shed some very interesting light on the subject I had not found anywhere else.
But regarding the rule “transport category helicopters are not required to demonstrate touchdown autorotation”, WTbleepingF?! Can you point me to any historical discussions on this lack of such a rule by the authorities having jurisdiction?
@ I watch CW occasionally, but he did his training in a Robinson. Far braver than I will ever be again. I paid for a ride in an R44 around the Hiller museum at KSQL once, but that was before I learned about mast bumping. I’m shuddering at that thought almost as much as if I were back in the right rear seat.
@@bzig4929 Could say, four JATO bottles, triggered by a radar altimeter slow an Osprey autorotation enough to be walk-away safe?
Very informative video. But the more interesting solution is to replace the turbine with a hydraulic motor with a hollow shaft. To control the overall pitch of the propeller. At the same time, there are no heavy units on the rotary wing console and there is no synchronizing shaft line...
Hydraulic motors are very inefficient, they will generate a ton of heat.
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Thanks!
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