Speed brakes

[jhausch]

So, did you figure out the issue?

 

[Jaybird180]

This is noteworthy:



Yearly:

Remove SpeedBrakes​

TM from aircraft​

d.)​

Clean and Inspect unit for damage, corrosion, looseness & proper operation​

e.) Lubricate worm and worm gear with Lubriplate. DO NOT USE SPRAY LUBRICANTS!

Every 50 hrs

Check drain tubes for debris​

​

​

​

​

​

Every 1000 hrs

​

.) Return SpeedBrakes​

TM to Precise Flight Inc. for​

Clutch Lubrication and Spring Replacement

Every 5000 hrs

d.) Return SpeedBrakes​

TM to Precise Flight Inc. for​

Drive Assembly Replacement


https://preciseflight.com/resources/doc/08059_Mooney_M20__M22.pdf

If the speed brakes have been removed IAW the maintenance instructions, can he aircraft be operated? Of course assuming paperwork (W&B and Logs) are updated.

 

[RotorAndWing]

You guys are making this waaaaaayyyy more complicated than it actually is.

 

[Ted]

So, did you figure out the issue?

Yes, the issue is that he expected a useful answer from PoA.

 

[Bill]

You guys are making this waaaaaayyyy more complicated than it actually is.

Glad my Mooney doesn't have speed brakes, KISS.

 

[EdFred]

If you're in cruise and you pull the prop back, the RPM changes... Does that mean it was producing drag?

Now, let's say we're at a relatively high RPM/low MP setting in level flight, right on the edge of the governing range for the prop (and thus at the low-pitch stop). Clearly we are not at zero thrust in that situation, as the engine is still keeping the plane in the air.

If we're right at zero thrust in the descent with the prop set at cruise RPM, pulling the prop back will increase blade pitch and the prop will slow down unless we're already at the coarse pitch stop. If we push the prop forward, it'll speed up unless we were already at the fine pitch stop.

Now, let's say we are at zero thrust and just barely touching the fine pitch stop in the descent with 14"MP / 2200RPM. We push the prop forward and nothing happens. But if we were already getting a little bit of drag (ie, negative thrust), we push the prop forward and it still won't change RPM despite us not being at zero thrust to start with.

I think finding the exact zero thrust point for a 155-knot, 500 fpm descent at 2200 RPM would involve first getting close via experience and feel, and then starting with the same MP and slightly lower RPM. Then, change RPM slowly until it starts increasing and then stops. If it stops at 2200, then you were right about the zero-thrust point - If it doesn't, adjust MP, stabilize and try again. Lotta variables to control for, though, so I'm not entirely positive this would work.

Who is in cruise at (near) idle throttle? Either way, any surface that produces lift (thrust) produces drag, so to return the smart-ass comment, yes, it does.

 

[Ted]

Glad my Mooney doesn't have speed brakes, KISS.

It's just like any other tool in the box. Gives you more options, but also means it's one more thing to break.

 

[Bill]

It's just like any other tool in the box. Gives you more options, but also means it's one more thing to break.

Just funning everyone. There are times I would have liked them, but I ain't paying to have them installed!

 

[flyingcheesehead]

So, did you figure out the issue?

Yes, the issue is that he expected a useful answer from PoA.

Ted wins the thread!

The issue is simply that I haven't paid my periodic ransom to Precise Flight, apparently!

You guys are making this waaaaaayyyy more complicated than it actually is.

Can you give us the simple answer then?

If the speed brakes have been removed IAW the maintenance instructions, can he aircraft be operated? Of course assuming paperwork (W&B and Logs) are updated.

Precise flight "can not recommend" flying with holes in the top of the wings, and suggests making a cover to screw in place of the speed brakes using them as a template. I seriously doubt there's any aerodynamic issue - They are far enough aft that Mooney didn't even use flush rivets in the area - but there might be increased risk of getting debris and dirt inside the wing. I've seen inside the wing of the plane and it is clean enough to eat off of.

Just funning everyone. There are times I would have liked them, but I ain't paying to have them installed!

Agreed. As much as I like having them, it'd be $6,000+ to have them newly installed and I don't think they're worth THAT much.

 

[flyingcheesehead]

Who is in cruise at (near) idle throttle? Either way, any surface that produces lift (thrust) produces drag, so to return the smart-ass comment, yes, it does.

Touché. But I'm merely trying to point out why I don't think your method of determining zero thrust would work. Nobody cruises near idle throttle, it was a thought experiment.

 

[bluerooster]

If the speed brakes have been removed IAW the maintenance instructions, can he aircraft be operated? Of course assuming paperwork (W&B and Logs) are updated.

Can you operate a Mooney with a relatively large, rectangular hole in the top of the wing?

 

[Mistake Not...]

Probably. The hole for mine, at least, isn't that big.

https://preciseflight.com/general-aviation/shop/product/speedbrakes-m20-series-mooney/

 

[Jimmy cooper]

On 4000' feet of runway if landed properly you wouldn't use wheel brakes even if you didn't have the speedbrakes. [/. I ve only flown a super 21 and a 201. In those two models , if you need speed brakes , you are not flying them correctly. On a 4000 foot runway very very little braking would be used, probably only to make a quick turn off the active. Very docile stable airplane if you keep your pattern speed down.

 

[Mistake Not...]

This has me wanting to go try some landings just to see how little rollout I can get away with. I'd say "short field", but I mean rollouts without brakes.

Speedbrakes, at least in my experience, aren't very effective at all at low speed. You can easily go around with them still out (part of my checkout in the mooney).

 

[Henning]

I would really like speed brakes on the 310. It's a lot like the Mooney in the sense that it doesn't like to slow down and go down at the same time. Actually it doesn't like slowing down at all.

Yep, they would be nice.

 

[flyingcheesehead]

Can you operate a Mooney with a relatively large, rectangular hole in the top of the wing?

The hole isn't that big. Fore-aft, it's probably less than an inch. I'd bet that the aileron gaps cause a bigger air disturbance than missing speed brakes... But I don't know with certainty.