update


Chris Walterson
 

Short update on the Q200 with the Soob.   My empty weight is 749.

 I have 13 hrs on it so far.  Had to adjust brake pedals to get more positive braking. Easy fix.  Replaced the fuel gauge with one that was compatable with the sender.

 Still waiting on the exhaust pipe to reposition exhaust down.

 Went for a buzz this morning. Managed to see 2,000 fpm climb with 8 lbs boost on takeoff.  Just me and minimum fuel.  More P factor than I am used to so there is a bit of right rudder. I see 160 mph indicated at 3200 Rpm and the prop [ three blade Warp Drive] set at 13.5 degrees.

 At 3200 rpm I still see 3 lbs boost with the boost control off. Haven't figured out fuel burn yet, but I am hoping  less than 5 GPH.

 I've been up to 175 indicated, but the airplane loves 160. Still need to dynamic balance everything, but as is it is pretty smooth.

 I have the SDS system so I can lean out with an adjusting knob.   I takeoff with boost at 12.5 mixture and then lean to 13.5 in cruise.

 My landing are not embarrasing. I can three point most times , but I do notice the sink rate is more than the Dragonfly.

 It flies hands off and I have the reflexor just ahead of the throttles so I can tweak the cruise and seldom need to use the elevator trim.

 So the testing is uneventfull so far. Need to expand the speed range , but I don't expect any surprises. Then it is a matter of loading up with 80 lb bags of cement to check out heavy performance. The bags wrapped in a blanket sit in the seat very well and can be buckled in, although if I every do have an accident the rescue guys are going to be shaking their heads.

Still having fun-------------  Chris



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Awesome update, and excited to hear more about your SDS system ... Mine is in the mail. Did you get both fuel injection and electronic ignition I assume?

Would love to see your firewall forward picture,

Robert
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Robert "TheFrisco" Schmid
(408) 805-5450

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Love building planes almost as much as flying. Latest completed build is "Loki", a Chinook Plus 2 bush plane.


Jay Scheevel
 

Sounds really good, Chris. You have clearly built a nice airplane. Do you have a reduction drive on you Subaru, or is that 3200, the crank speed.

About the sink rate. Keep in mind that there is a "'minimum airspeed" on this type of canard configuration. If you get close to that, the whole airplane will try to make up speed using sink. Feels about like an incipient stall in a standard configuration w/laminar flow wing, but for a completely different reason. Mine starts that sink at about 75 mph indicated, but does not pitch buck until 70-71 mph depending on loading. So I usually get in right near the runway at about 80 mph, hold that pitch, then it will bleed to 75 and set itself down nicely. It sounds like you may be looking at similar numbers, but with TD configuration. Mine is a Tri-Q. We are close to the same weight.

Cheers,
Jay

-----Original Message-----
From: main@Q-List.groups.io <main@Q-List.groups.io> On Behalf Of Chris Walterson
Sent: Wednesday, June 29, 2022 7:43 AM
To: main@Q-List.groups.io
Subject: [Q-List] update

Short update on the Q200 with the Soob. My empty weight is 749.

I have 13 hrs on it so far. Had to adjust brake pedals to get more positive braking. Easy fix. Replaced the fuel gauge with one that was compatable with the sender.

Still waiting on the exhaust pipe to reposition exhaust down.

Went for a buzz this morning. Managed to see 2,000 fpm climb with 8 lbs boost on takeoff. Just me and minimum fuel. More P factor than I am used to so there is a bit of right rudder. I see 160 mph indicated at
3200 Rpm and the prop [ three blade Warp Drive] set at 13.5 degrees.

At 3200 rpm I still see 3 lbs boost with the boost control off.
Haven't figured out fuel burn yet, but I am hoping less than 5 GPH.

I've been up to 175 indicated, but the airplane loves 160. Still need to dynamic balance everything, but as is it is pretty smooth.

I have the SDS system so I can lean out with an adjusting knob. I takeoff with boost at 12.5 mixture and then lean to 13.5 in cruise.

My landing are not embarrasing. I can three point most times , but I do notice the sink rate is more than the Dragonfly.

It flies hands off and I have the reflexor just ahead of the throttles so I can tweak the cruise and seldom need to use the elevator trim.

So the testing is uneventfull so far. Need to expand the speed range , but I don't expect any surprises. Then it is a matter of loading up with
80 lb bags of cement to check out heavy performance. The bags wrapped in a blanket sit in the seat very well and can be buckled in, although if I every do have an accident the rescue guys are going to be shaking their heads.

Still having fun------------- Chris



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Chris Walterson
 

Jay------ I did the stall / porpoise on the first flight to feel it out. Really non eventfull and much like you described.

 The 3200 rpm is in a direct drive configuration. I will take it up to 4,000 eventually. I think my prop is 56 inches diameter.

 Also, in one of my other posts, I had mentioned in level flight my fuselage is 3 degrees down when measured at the armrest.

 I am pretty sure I built it exactly as the plans say, so has anyone else measured their fuselage angle in level flight?

 I just used my digital level on the passenger arm rest for reference. Maybe something to try on your next flight Jay.

 take care-----------  Chris


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Jay Scheevel
 

Hi Chris,
Looking at your numbers again, and in light of your question about pitch. I think for your plane -3 degrees (3 degrees nose down) is not realistic. Perhaps your arm rest is not zero wrt to the wings (the wings are really the only things that matter, not the fuselage). The chart below is from my modeling. Your plane has a decalage of -1, based on the pictures you sent me. This is the same as the QAC factory demonstrator N81QA (actual flight test data from N81QA is plotted as stars on this plot. Based on the fact that you are 3-pointing your landings and your ground posture must be close to +7 (again, based on your photos), I think the most forward pitch you could see in flight, at the higher airspeeds (160 IAS and above) is ~0 degrees.

The bottom plot is my airplane performance during a recent flight. My plane has a decalage of -2, so my data should plot on the orange line in the model. I have captured a screen plot of level flight for about 1 minute at ~155 mph indicated, and the average pitch is about +1.6. I calibrated my EFIS pitch to match my canard incidence, whiich has level line at 0 pitch per plans (my main wing is set pitch down -2, to yield decalage of -2). So my flight data is consistent with the model's orange line at 155 IAS/CAS.
Cheers,
Jay


Chris Walterson
 

Jay--------------  Thanks for the info------------  I will go check again next flight. Maybe my passenger consol is off so  I will use the center one as that is the one I built the airplane to. A little bit more info is that the elevators are exactly in trail. No up, and no down and the ailerons are about 1/4 inch up for comfortable flight. I will play with the reflexor and the elevator trim and see what happens while checking the fuselage level.

 Thanks again for all your expertise.---------------  Chris



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Michael Dunning
 

At 3200 rpm I still see 3 lbs boost with the boost control off.

From 1992-2014 (at minimum, personal experience) the stock, unloaded, Subaru wastegate spring was 2.90-4.35 psi (0.2-0.3 bar) so it looks like you're right on the money! Best of luck and looking forward to more reports of your test flying.
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-MD
#2827 (still thinking about planning on visualizing how to finish building)


Chris Walterson
 

Michael------  Regarding turbo  boost. I do not use the stock waste gate system.I have a manual waste gate controlled by a cable. This way, I can either have boost or not.  The 3 lb boost is with waste gate open, but because the wheel is spinning 10 x the rpm I still get pressure.

 If I slow the rpm to around 2900 the boost drops to  1-2 lbs. I have had the manual system on my other airplane for 25 years and always works well.

 I have seen 10 lbs boost, but I am not using turbo pistons so I only see that amount of boost if really needed.

 Take care-------------  Chris


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Chris Walterson
 

Jay-----------------  Maybe sniffed too much epoxi, because I can't remember where I got the 3 degree from. I could of been flying slow when I observed that. Went flying this morning and took the level. One thing I noticed that I was seeing  minus, but it was actually +, nose up. . So, what I found out is that at 2900 rpm and 140 mph indicated with airplane trimmed out I see about 2 degrees degree nose up.

I increased the speed to 160 mph , trimmed out and see .5 degrees nose up. Close to level.

 I tried to use reflexor to get the nose more down, but I ended up having more elevator pressure. The airplane didn't like it.

 It now appears the fuselage, wing and canard have a pretty good relationship.

 It works well and I am pleased.  Take care------------------- Chris














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