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True Airspeed figures

RV10inOz

RV10inOz

Well Known Member
Hi folks,

This is often a topic of much "mine is bigger than yours" kind of banter.....but I am genuinely interested in the actual performance numbers RV-10 owners have been achieving and at what fuel flow and power / rpm they are achieving it.

The RV-10 will have a sweet spot no doubt and with different engines and props there will be a spread for sure.

So confess your sins...I mean speeds!

We have just about run in our engine so up to the higher levels to see what ours will do. I am manily interested in 5000 -10000 feet ranges as we do not have a need to go higher here due lack of large rocks!:eek:

Cheers
DB
 
the -10 forum has the sins confessed.
Do a search of KTAS and you will see lots of performance data and the cooresponding powerplants.
Lots of discussion on this at your fingertips.
 
Got up today and ran a simple 4 course speed test. The GPS speed in the spreadsheet is GPS Ground Speed. Looks like 175.5 Knots?.average.

Set 1 Set 2
Heading GPS TAS (GRT) GPS TAS (GRT)
360 177.0 173.0 179.0 172.0
270 169.0 173.0 168.0 172.0
180 173.0 172.0 172.0 172.0
090 183.0 171.0 183.0 172.0
Average (Knots) 175.5 172.3 175.5 172.0
Average (MPH) 202.0 198.2 202.0 198.0

Flight Conditions
RPM 2440
MP 22.3
Fuel Flow 14.8
OAT 56
Baro Presure 30.21
Pressure Altitude 9000
Density Altitude 10849
Weight 2148
C/G 110.54





Looks like my indicated air speed may be a little low??
 
Thanks Rene

Very interesting!

And to Kahuna, yes there were pages of stuff. I would love to know how Glen created the massive improvement, was it horiz stab adjustment? I will be looking closely this weekend as we take some serious numbers on a long haul, and will be trying to peer around the corner at the elevator horns!

Getting the flaps up and ailerons trimmed well is kind of helpful too!
 
RV10inOz said:
Thanks Rene

I would love to know how Glen created the massive improvement, was it horiz stab adjustment? I will be looking closely this weekend as we take some serious numbers on a long haul, and will be trying to peer around the corner at the elevator horns!

Getting the flaps up and ailerons trimmed well is kind of helpful too!
Click to expand...

Could you put a link to this? I've been thinking the elevator is costing speed on the 9's and this might be what I've been looking for?
 
Bryan

I do not have enough time right now to find that link, but if you wish, search KTAS in the RV-10 forum and read each thread right trough.

Somewhere in there was a comment about removing a 1/4 or 3/16 spacer and replacing it with a 1/8.

It was something to do with the trim and angle of the elevator in level flight and if the elvator is presenting those big horns to the airstream there will be a huge amount of drag off them.

I will look again at work.......... CYA!

DB:)
 
OK, 15 hours over the last 3 days and I can not get anywhere near the figures Rene posted or the ones claimed on another thread.

So I am off on a hunt to eliminate drag where ever I can find it. I would appreciate any comments from the experienced -10 bulders on where these knots are hiding! Is it wing rigging? Horizontal stabs? elevator trim? Fairings....paint colour! :D

Here are some pics over the last few days showing the numbers! And she was at MAX weight..... ;)

4525920200a11267922318l.jpg


4525920200a11267922329l.jpg


4525920200a11267922344l.jpg


4525920200a11249277977l.jpg


Thanks in advance!

DB:cool:
 
The RPM range from say 2200 to 2400 seems to make only minor differences. The various photos also show different power settings depending on altitude and fuel range!

Either way you look at it, the top photo is around 74% power and a TAS of 160. And for those wondering about static systems and pitiot systems they have just been passed by the LAME to our AD/Inst9 which is the FAA's tests with an Aussie letterhead.

Would appreciate any things to look into to reduce drag.

Thanks

DB
 
Its my understanding that the ADinst 9 will not necessarily indicate that your airspeed sytem is providing accurate data. It confirms no leaks and may even correlate pressures to a corresponding IAS.
But until you have verified your system in flight with either a 4 way or 3 way run comparing GPS GS with TAS, CAS and IAS you will not know if your system is correct. A lot of it has to do with the way your static system behaves at various airspeeds. There are a couple of ways it can be done, I am sure they have been discussed here before. It needs to be done over the range of airspeeds from approach to top speed. You may find that its accurate up to and IAS of 130kts then starts to indicate incorrectly, hence the reason for testing at various airspeeds.

You may have already done this as its part of the test flight procedure but if not you may find a few knots. If I am teaching you to suck eggs then I apologise.
 
Quick observation... looks like a decent bit of nose down elevator in your pic. Is that an illusion, or is that typical for your plane?

Keep us informed of what you find.
 
Chris, You raise a good point, it may be that at higher speeds it becomes less accurate, I will do some more tests this weekend and see what we get.

Flyer.....That shot was taken from a Bonanza with ALT Hold engaged, I was positioning around it, and it was not a perfectly smooth bit of air so it is quite likely I had stick forward.

Will report back later with any improvements!
 
Couple of 1000 NM trips under my belt recently. I find that I get in the neighborhood of 150 KTAS (give or take 5 knots) at altitudes ranging from 7000' to 11,000' running WOT at the higher altitudes and 2370 RPM, 50 degrees LOP. CHT's run in the 320's to 340's, oil temp around 180. My elevator is pretty much even with the stab with luggage in the rear and two of us in the front seats. Fuel flows are generally 8.7 to 9.3 gph in these scenarios. 50 to 100 degrees ROP gives me 160-165 KTAS at about 12.5 -13.0 gph.
 
Static vents is where it is at........... if you have not tested the speeds via a GPS box you may in fact be well out in your static...... hence altitudes and transponder outputs.

VERY EYE OPENING............... Thanks to Wayne for his tips.

This is a serious issue as I was able to make a small adjustmet and go from -9 to +7 in an instant, yest the GPS box said 175.5 and 175.4......... and the Altimeter .... :eek:

Will report more, but the variation could well have you outside the standards for transponders. Not very funny at all.

DB:cool:
 
Trim Drag

Bryan Wood said:
Could you put a link to this? I've been thinking the elevator is costing speed on the 9's and this might be what I've been looking for?
Click to expand...

Trim drag can account for up to 5-6% of your total drag. Fortunately, it's easy to get rid of. Just fly with your CG near the aft limit and you will have minimum trim drag.

-David
 
And as a follow up, it seems many folk have a problem with their static and do not realise it. I found another RV-10 on the weekend that is out by a bit!

I finally have our sorted I believe! :)
 
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