Aeronca Thrust Reversers

[bubble]

How do Aeronca thrust reversers work on the Lear 35? Do they redirect all of the air coming out of the tailpipes or just the fan air?

Thanks!

 

[NCherches]

Hum... forgot but they will kill you if you don't EMER STOW them asap on a takeoff roll

 

[BN2A]

High pressure bleed air moves a cascading mechanism which allows the end of the tailpipe to slide aft. Blocker doors also actuate and the air from the high bypass side is directed out of the vanes.

Clear as mud?

 

[bubble]

So in other words the core exhaust is still blowing backwards when the reversers are deployed?

 

[Basil]

Nope. When the blocker doors close they divert all exhaust (bypass duct and core exhaust ) into the cascade vanes which redirect it forward.

 

[propsarebest]

Are they really as bad as everyone says they are?

And why then are the buckets so much better?

 

[LRvsH25B]

Are they really as bad as everyone says they are?

It's not they they are "BAD" in terms of being effective, as a matter of fact, just the opposite, they are very effective. The problem with them is they require a lot of MX (lubrication of the rails the Cascades slide on, blocker doors, etc). Also, since they are actuated via bleed air, depending on the aircraft, when you ask for reverse power, the T/R's have to get the air from some place, and that can take a little longer than you want at times. So if the bleeds are still on in the cabin, for example, the T/R will probably take away from those and route it to the T/Rs. At least that is how it was in the LR55 that I flew for about 6 weeks in my 1st job. I don't know that the systems were set up that way, but you could hear it happening. Also, they both have to be working to use. For example, on a single engine landing, you ahve to bring the dead engine out of cut off just to use the remaining T/R. Also, if the vanes dont deploy, you usually know that because the plane starts accelerating again when it should be slowing!

And why then are the buckets so much better?

The 'Target" type or buckets are extremely effective as well. What's nice about them is that when they are deployed, even at idle thrust, they are working aerodynamically. They deploy into the airstream, so even when you just "crack" them, they are grabbing a chunk of air and slowing the aircraft or at least keeping it from accelerating. The system is very simple as well. Most have an "emergency stow" button incase of inflight deployment. This Gulfstream is the 1st plane I have flown that does not have that feature. If the T/R deploys, it'll either rip off or the other engine has enough raw power to handle it's BID-ness.

Someone might have a better answer for you than what I just threw out there, but that has been my understanding of the systems, and it seems to have worked well for me.

 

[avbug]

The aeroncas aren't particularly effective, do fail to deploy, fail to retract, and have been known to inadvertantly deploy...there hasn't been a case of that happening with the dee howard.

A lot of folks prefer the clean configuration with no T/R's. I've flown all of them, prefer the dee howard, and prefer the slick airplane sans the reversers, after that.

 

[Gulfstream 200]

I liked the 35s with DeeHowards better

Aeroncas never came out evenly, always made for more work....to the point where nobody used them and that likely made them worse..

 

[NCherches]

When I was in the lear we didn't even test them prior to flight because if you did you were just asking for it to not retract . . . Just not reliable, kind of like the old Lear itself. Fun plane to fly, but I don't really miss it either

 

[2dumb2drive]

I'm sure that there are mechanics out there that can keep the aeroncas in good working order. Ours can not. We do not even use them anymore because it was leading to so many break downs on the road. I can't tell you how many times I have had to shut down an engine after using them on landing and one would just be stuck fully deployed. I've also aborted two takeoffs because right after t/o power was set the horn and unlock light on one of them would activate. Not fun.

 

[bubble]

Sorry I've been away from the computer for awhile. Thanks for the info guys!

 

[Lead Sled]

It's been a million years since I last flew a 35 with Aeronca's, but I've got close to 3,000 hours in them. We suffered through all of the problems that go along with Aeronca's and ended up pinning them for most of our flights until we came upon a Lear maintenance guru. (Who just happened to live down the street from me.) This guy started turning wrenches for Bill Lear back in 1965 and had spent his entire career working on Lears. He had our Aeroncas tuned up and working properly in less than one day. After that, we never had another problem with them in close to 2000 hours of flight time. Believe it or not, the big problem was excess lubrication. ("If this much is good, this much more has to be better, and here's some more just to be sure...") After that, all they ever needed was the routine stuff on the inspections. They worked great.

Once we got the maintenance issues sorted out with them I actually preferred them to the Dee Howards - they were much more effective.

LS

 

[Gearmonkey]

I know you guys are talking 30 series TR's, but the 25's with Dee Howards, ohhhhhh man, now that was fun stuff!