Has anyone ever...?

[Johnnybgoode]

I did it, and it seems faster.

Problem is I had never done the fancy 3-way tests to determine speed. I did put in the AV-20S and was surprised to see 153kts TAS the past 2 days while flying. I have an overhauled engine and am breaking it in, so not going easy on it, but this number surprised me.

I have no speed mods, to speak of, except the brake reversal STC. Well, and the lower cowl closure, which isn't really a speed thing.

More testing to follow. So far I have only taped up cowl seams and the forward set of underwing ports.

Open to ideas on how to test my pitot system for accuracy. I suppose that avionics guys have a tester they use to pressurize and test it, right?

[Marauder]

  On 4/25/2019 at 11:33 AM, Johnnybgoode said:

I did it, and it seems faster.
Problem is I had never done the fancy 3-way tests to determine speed. I did put in the AV-20S and was surprised to see 153kts TAS the past 2 days while flying. I have an overhauled engine and am breaking it in, so not going easy on it, but this number surprised me.
I have no speed mods, to speak of, except the brake reversal STC. Well, and the lower cowl closure, which isn't really a speed thing.
More testing to follow. So far I have only taped up cowl seams and the forward set of underwing ports.
Open to ideas on how to test my pitot system for accuracy. I suppose that avionics guys have a tester they use to pressurize and test it, right?

The TAS on these units is calculated using various factors. One factor it doesn’t add in is the CAS. You should look at the POH for the altitude and KIAS you flew and see how many knots difference it is. It may be as much as 3 knots.


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[cliffy]

One caution for safety  Keep the spanways lengths of tape short so IF one was to come undone and lift only a short spanways area would be affected. There have been fabric airplanes where the fabric has lifted spanways and caused accidents with loss of lift and drag. Try not to connect these tapes or overlap them so one can lift another. Orientation fore and aft with the airstream is best. 

[steingar]

Sounds like a pain.  The tape, and all its glue, has to come off at annual.  Those are inspection plates.

[Johnnybgoode]

I was an engineer before a pilot and so the testing part is interesting to me. Don't mind the effort, which is actually nil. The 3M tape leaves no residue. And I have had no tape lift over 5.5 hours of flying. Thanks too for the alignment advice.

Edited April 25, 2019 by Johnnybgoode

[David Lloyd]

One time on the RV I taped every ridge, every seam, every junction that looked like it may cause drag.  Maybe, maybe it was slightly faster.  Maybe.  Less than about  3 knots it is very difficult to tell.  One day to the next, different temps, different pressures, different fuel load, etc. makes it difficult to see a small difference.  Ripped all the tape off and never looked back.

[Johnnybgoode]

  On 4/25/2019 at 6:41 PM, David Lloyd said:

One time on the RV I taped every ridge, every seam, every junction that looked like it may cause drag.  Maybe, maybe it was slightly faster.  Maybe.  Less than about  3 knots it is very difficult to tell.  One day to the next, different temps, different pressures, different fuel load, etc. makes it difficult to see a small difference.  Ripped all the tape off and never looked back.

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Which RV do you fly?

[steingar]

  On 4/25/2019 at 7:30 PM, Johnnybgoode said:

Which RV do you fly?

Expand  

An untaped one.

[David Lloyd]

RV7.  Think it is sold, money to be wired Friday.  We'll see.  Mooney next.  Might have to fly a Bo till a Mooney is purchased.

[Johnnybgoode]

The thing I find interesting is that my RV-4 has one inspection portal under each wing and it is a beautifully flush mounted, handmade piece. No need for tape there.

is there only one under the -7 also?

[David Lloyd]

3 Each side.

[carusoam]

David, it looks like you built a construction facility first, to build your plane in...

Order of flight is important...

Bo before Mooney... all good, not looney....

Mooney before bo... leaves a pilot longing to get back...

Go Mooney!

-a-