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-   -   AOA or stall horn question. (https://vansairforce.net/community/showthread.php?t=113057)

skyking902001 05-16-2014 10:42 AM

Quote:

Originally Posted by Sig600 (Post 880336)
This is what I was going to post.


Beware, so many cool toys out there your wallet will get really light really fast!!! :)

There must be some sort of relationship between weight of airplane and weight of wallet. As airplane weight increases, wallet weight decreases--roughly in a ratio of about 1 to 100. 1 pound of aircraft = 100 dollars, thus 1200 lbs empty weight of airplane should lighten your wallet by approx. $120,000. This is just a casual observation on my part--YMMV.

jester 05-16-2014 01:49 PM

I have an MGL efis and I fly 720. I appreciate all the responses .I am looking up each system mentioned . I have to have one now that I have seen them on u-tube.

Finley Atherton 05-16-2014 02:53 PM

I flew for many hours with the Vans stall warning vane then removed it and replaced it with the Dynon AoA as part of an IFR upgrade.
My home airstrip is short and sometimes marginal so slow, precise approaches are required.
I suppose that the AoA may give slightly earlier warning of an impending stall but IMHO the AoA gives me no extra benefit during the approach over the (correctly calibrated) simple vane stall warning.

Fin
9A

Bill_H 05-16-2014 03:24 PM

You do not "have" to have the combo Dynon pitot to get AOA on the Dynon. The RV12 world found a $10 substitute that works great. Read this thread, particularly starting page 2. I used the inflation needle, others found a rivet worked as well.
http://www.vansairforce.com/communit...ad.php?t=34040

Picture inslalled here: http://www.vansairforce.com/communit...&postcount=183

The great thing about the Dynon is the AUDIBLE AOA indication in your headset. Increasing frequency at higher angles. You can ride the right beeping frequency all the way to the runway threshold. You don't want to be looking down at the Dynon screen when going into a 1260 foot strip... If you get a different AOA, be sure it has audible.

mike newall 05-16-2014 03:41 PM

I will caveat my original comment with the fact that the AOA is only as good as the calibration, and that is very important.

The Dynon uses a series of increasingly interesting manoeuvres culminating with full power stalls.

Now, with my mature Brother squealing like a girl as I am eaking the last drop out of the poor, complaining airplane, we finished the calibration.....:rolleyes:

Full power stalls in an RV are quite interesting.

I digress - what you end up with is a superb tool to help you in all areas of flight, not just approach.

This year, biennial flight revues in the UK are featuring crosswind stalls in the pattern - distraction during the climb out can be as dangerous as the base turn/final situation.

It is interesting to watch the AOA as you are doing aeros - it gives you a real impression as to what is happening - particularly on the back side of looping figures - sadly the statistics show too many accidents where guys pull too hard on the back side of a loop and flick out.

I will try and set up my GoPro soon and see if we can get some footage.

rightrudder 05-16-2014 04:06 PM

Quote:

Originally Posted by mike newall (Post 880399)
Full power stalls in an RV are quite interesting.

How so? Crazy wing drop?

I have a friend who flies a Starduster bipe who pulled too hard out of a loop, and regained consciousness after losing about 3000 ft of altitude. Lucky guy!

Sig600 05-16-2014 06:19 PM

Quote:

Originally Posted by rightrudder (Post 880406)
How so? Crazy wing drop?

I have a friend who flies a Starduster bipe who pulled too hard out of a loop, and regained consciousness after losing about 3000 ft of altitude. Lucky guy!

Power to weight ratio, you're cocked up uncomfortably high and slow when it breaks (depending on horsepower/weight).

mike newall 05-17-2014 03:19 AM

Doug,

No - we have an MT 3 blade prop which works well at low speed.

We ended up at a very high nose up, still flying and fully controllable - it was insane.

I guess when it stalled, we must have been 30? nose up.

No wing drop, just a rather large nose drop as I took the power off.

F1R 05-17-2014 06:40 AM

You do have one
 
Quote:

Originally Posted by jester (Post 880374)
I have an MGL efis and I fly 720. I appreciate all the responses .I am looking up each system mentioned . I have to have one now that I have seen them on u-tube.

Depending on the viewable field of your pitch ladder of your EFIS you in essence may already have an AOA indicator. The waterline symbol represents your longitudinal axis of your ship (where the nose is pointing). The velocity vector represents your actual flight path. The difference between the two is your effective angle of attack. Any time your AOA is over 14 degrees and approaching 15-17 degrees you are nearing your limit. This is only GPS flight path derived info not actual airflow based but if your EFIS can display 15 degrees of pitch below the waterline, it would make for an interesting experiment at a safe altitude to try some simulated stable approaches compared to an LRI or the various AOA displays.

If you trim pitch neutral for cruise, then do not trim for slow flight the pressure on your fingers holding the stick will be in a more feel able/tactile relationship to your AOA increasing at landing speeds. The burble and buffet as the wing approaches stall is easier to feel.

No doubt I will get roasted on both points.

YellowPeril 05-17-2014 11:28 AM

http://www.vansairforce.net/safety/2nd_99.pdf


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