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Old 04-13-2017, 12:33 PM
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logansc logansc is offline
Join Date: Feb 2005
Posts: 515
Default Revamping my Rocket: Questions

Rocket guys: I have a considerable difference between my old ASI and the "tape" airspeed in my new AF5600. I've flown several NTPS TAS multi-heading tests using GPS and have established (I think) that my AF5600 is reading about 10 knots high based on calculated GPS derived TAS versus the TAS displayed by the 5600 (my old ASI which I still have, is even further off---long story). Anyway, I adjusted the airspeed indication on the AF5600 calibration page down by 10 knots. Now of course, it seems too low.

1. Can anyone tell me about the 54 knot "stall speed" in the specifications of the sport wing Rocket? In further testing, I did several stalls today and was seeing 47-48 knots indicated on the tape and around 60 on the old ASI when it broke with very little difference (except deck angle) between power on, power off, and flaps up or down. Into the bargain, with these settings I am way down (as expected) on the indication at the top end. I always thought my Rocket was pretty fast, but apparently not! On a follow-on full power test, I was only seeing 195 kias or so on the AF5600 at 200' and WOT (75 degree day). I was seeing around 210 on the old ASI at the same time. If 54 knots for the stall is actually about right, it seems to me I can add around 5-6 knots back into the 5600 tape display. That won't jive with the GPS derived TAS speeds though, but I can't believe the airplane is not stalling until a real world 47-48 knots with one 200 pounder and near full fuel on board. I know airspeeds vary a bit (sometimes fairly significantly) across the range of speeds a typical airplane is capable of, but this seems like a bit more than I expected. Regardless, accuracy at the bottom end of the scale is more important to me that at the top, so...

2. My TruTrak Gemini autopilot settings have gotten all gooned up trying to follow the guidance in the 5600 manual. Is anyone flying the Sport-Rocket/Gemini combo who could share their settings with me?

Thanks very much!

Lee Logan
Ridgeland, SC (3J1)
F1 Rocket #160 flying
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Old 04-13-2017, 01:26 PM
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SMO SMO is offline
Join Date: Oct 2007
Location: Salmon Arm, BC
Posts: 859

Hi Lee, not sure this is a lot of help as my F1 has the EVO wing, but solo with 20 - 30 gallons of fuel I stall at ~57 knots, full power or full flap both drop the stall speed by ~5 knots.

With respect to airspeed, I assume you have tested your static system for leaks. I burned up quite a few dinosaurs messing with my static port but finally got it nailed - ASI is very accurate.

Here is a picture of the dam in front of the static port - same on both sides. That is a piece of .032 glued to the fuse. Static ports are behind the rear baggage bulkhead.

Mark Olson
1987 RV-4 Sold
2003 Super Decathlon - Sold
F1 EVO Rocket, first flight May 31/14
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Old 04-13-2017, 01:38 PM
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Toobuilder Toobuilder is offline
Join Date: Jul 2009
Location: Mojave
Posts: 3,475

Lee, I wish I could go out and fly to verify, but a stall in the mid 50's is what I remember. Mid 40's is highly suspect.
WARNING! Incorrect design and/or fabrication of aircraft and/or components may result in injury or death. Information presented in this post is based on my own experience - Reader has sole responsibility for determining accuracy or suitability for use.

Michael Robinson
Harmon Rocket II -SDS EFI instalation in work
RV-8 - Flying
1940 Taylorcraft BL-65 -flying
PA-20-inspired "family truckster" -in work
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Old 04-14-2017, 06:32 AM
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logansc logansc is offline
Join Date: Feb 2005
Posts: 515

Thanks guys; I'm confident it's now reading low on slower speeds and maybe even a bit low on the upper too. I think I'll crank it back up a few knots and see how that goes until the IFR calibration "guy" gets back here next month.

In the meantime, anyone have an answer to question number two about settings for my Gemini?

Lee Logan
Ridgeland, SC (3J1)
F1 Rocket #160 flying
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