ado9518

To flycatch
I measure CG from wing panels joint.

To ColeTrane
I think you have a point here. I just assumed that incidence was set up rigth by manufacturer but you know ...
I'm going to measure incidence and try to figure out possible improvements.

Have nice fligths!

RCVFR

My Feedback: (7)

When I started flying my Phaeton 90 bipe, I was not happy with inverted performance. This is not a "muscle" plane, but a sport type. Power was a 25cc gas engine, adequate but not overpowered, in other words, it flies on the wing. In talking with Dave at Balsa USA, he suggested making the top wing negative to the bottom, which I did by inserting spacers under the top trailing edge. It made a big difference. 11 years later, I have it torn down for recovering and a new paint job.I love the way this plane flies.

cubcrasher

My Feedback: (6)

Hobby  People has the Black Horse Pitts on sale again.
A little bit more this time $289.00,still seems like a bargin to me

mrbigg

My Feedback: (21)

Still a good price. I had mine out of the box checking it out a while back. Really nice plane. You could not even come close to building it for that cash.

handyman 220

My Feedback: (54)

If I didn't already have one, i wouldn't think twice about paying that price! The kit is definitely worth the money.

cubcrasher

My Feedback: (6)

I got mine at the July 4th sale for $199.00, talk about bargin.
I should have ordered two.
Hobby People usually have a good sale around April, just in time for an income tax check refund.
They usually have a good sale on Magnum four strokes at that time.

telejojo

I bought 4 Magnum 4 st 52s when they had them on sale for 79.99 a year or 2 ago but have not seen them for that since.............

cubcrasher

My Feedback: (6)

telejojo,
Now that's what you call a power buy.

ColeTrane

My Feedback: (1)

Thanks for the response... basically your saying that yourtop wing has less incidence(AOA) vs the bottom, correct? Do you know what the wings are, incidence wise, vs your horizontal stabilizer?

Thanks
C-

ColeTrane

My Feedback: (1)

Have you got a chance to see what yours was from the factory?

Honestly, all the ARF'sI purchase get an incidence meter thrown at em just to verify what was built by the manufacturer. It also identifies flight characteristics, both good and bad, before they even get in the air...... then you "know" what you have, not assumuptions by an overseas "economy" model airplane manufacturer. Not saying that all are like this, but you do pay for what ya get and were paying for some sort of engineering.....

RCVFR

My Feedback: (7)

The plane is dissassembled right now, so I can't check incidence. However, don't overthink this. The basic set up is around "0" "0" to the stab. The bottom may be+1 and the top -1 or -2. Just as in full scale, the models need to be "rigged" to find the best performance. When I experimented with spacers under the top wing, I started with around 3/32 stock, checked for flight, increased untill around 3mm which seemed the best. So, I can't tell you the incidence, but its at where the plane flies well. When you fly it, the plane will let you what it likes best.

ado9518

I was quite surprised to measure an incidence of -0.5° on three wings and -1.5° on upper rigth wing. This explained the need of left aileron trim on first fligths.
Lower wing has a very tigth fit to fuselage, so I kept it "as is" and set upper wing to +1° relative by shimming front strut and cabane. I had to add quite a bit of down trim on elevator, but besides this I didn't notice variation on performance. I espect an improvement in stall performance, but I definitely prefer to stay away from stall conditions ...
Got a good inverted flight increasing elevator throw.
This is my second ARF model and Ihave to admit that material and sometimes engineering is very far from a scratch built model, but I wouldn't be able to build it for the same money and it would require me an HUGE amount of time.
It will need a further tuning, but overall I am satisfied with it.

Have neice flights!

bps

My Feedback: (3)

My Pitts has flown! It went very well but needed some rudder and aileron trim for level flight. Without a doubt it needs more right thrust in the motor. The DLE 30cc on a 18x6 prop is a great combination and has a lot of torque. The elevator and rudder throw was double what the instruction stated. The elevator needs more because I could not get the plane to stall at idle. It would just mush and sink. On landing I ran out of elevator and the plane bounced just a bit, added a touch of throttle and it settled back in. CG could go back even further than I have it set for now. Instructions call for 77mm or about 3". Mine is set at 3 3/4" and I plan on moving it back another 1/2" just a little at a time.

Here are my control settings

Aileron 3/4" up and down
Elevator 1 1/2" up and down, going to 2"
Rudder 1 1/4" left and right, going to 2"

30% expo on all surfaces.

Next flight in a couple of weeks due to prior commiitments.

flycatch

My Feedback: (26)

Excellent debrief however the CG placement has a lot to do with elevator throw adjustments. You commented on adding right thrust because you added rudder trim. Tell me how much right rudder did you add during takeoff. Once airborne and flying straight and level how much right rudder trim did you add. If the engine is set-up at with little or no right thrust than this problem would show up only during takeoff, not once airborne. It appears to me that your vertical stabilizer is offset to the left. or your horizontal stabilizer is not 90 degrees square to the vertical stabilizer. You need to take some measurements and make sure the vertical and hoizontal stabilizers are square to oneanother. Remember there is a big difference between a turn and bank.

I have not maidened mine yet and I'm using a Saito 1.8 FS turning the same size propellor as your. After what you said I'll pay attention to whats going on once airborne. Last thing to remeber is throttle setting in relationship to triming an airplane. Trim for a setting usually 3/4 throttle and anything above or below this setting you fly the plane.

bps

My Feedback: (3)

Yes all good points. I have a small amount of right thrust in the engine. Lateral balance is good as well. The plane takes a bunch of right rudder on take off and in flight a fair amount of rudder as well. The vertical stab is aligns well and the horizontal stab is square as well. I think about another degree of right thrust will take care of the problem.

cubcrasher

My Feedback: (6)

Wonder what.s going on?
It doesn't look like Hobby People is stocking this plane any longer.

bps

My Feedback: (3)

I am happy with mine now that I have adjusted the cg rearward. The DLE 30cc pulls is along very well!

JariV

I've got one of these also in the works. Near completion. Waiting on the on-board-glow system.

CG discussion was very helpful and I need to check the incidences.

By the way; everybody is shimming the front attaching tubes higher. Why not lowering the rears upper bolt hole?

How does the added incidence of upper wing affect inverted flight? Requires a lot of push on the elevator? Barrel rolls become much larger in dia?

My choice for engine is OS FF-320. Will most likely use a 21x10 prop. Yes, there is enough ground clearance with original tires but I changed those to 100mm dia inflatable tires with wheels to absorb the shocks better.

Pics:

mrbigg

My Feedback: (21)

Nice.

stuntflyr

Super good looking. Here was my full sized Pitts Special back a few years. Yours looks very authentic with that four bangeron the front.
Chris...

JariV

Thank you.

Stuntflyr, how did you like your real Pitts? I'm planning on getting myself a real one too. I've never flown a taildragger but I plan to get lessons for that next summer. I would be interested in hearing real user experiences, not sales talk.

ado9518

JariV, your setup looks outstanding.
Did you reinforce the original firewall? It is just 3mm lite ply (don't ask how I know) and looks like a 2.2Kg engine could be demanding to it.
I would suggest to move CG futher back than 77mm recommended by manual and to increase elevator's throw.
Ifound that with CG and throws set as per instruction manual, inverted fligth was very difficult.

JariV

Thanks ado,

I did reinforce the firewall. That engine requires 15mm of plywood for mounting surface so the black plate is of that thickness. I also re-glued all the seams inside and glued additional plywood inside.

I will also move the CG backwards, currently I'm at 80mm but will move it additional 5mm at least. And I also already have longer throws in all surfaces, as instructed earlier in this thread.

Kostas1

OMG Jariv!!!!!!!

JariV

OMG about what?

If that was a compliment then thanks. But this build is nothing that has not been seen many times before. Usually these engines are stuffed into slightly larger birds but the cowl size of this plane looks like it is designed for the FF-320. Everything fits like a glove.