As you may have read by some of my other post I have a TF Arrow that I have built and ready to put in the air. My big concern is that the OS .61 is going to be way under powered after hearing some others input. Can't really afford to buy another engine. I did purchase some additional props such as a 13X6, 12X6, and a 11X7 to try and get more power out of the 61. I do have a Magnum 70 four stroke which would require replacing the mount and maybe modifying the cowling. If in fact the .61 is way underpowered for this plane what is the best approach to flying this thing on its first flight? What prop should I start with? I just don't have the experience on this type of situation and as much as I don't want to put more work into the plane I don't want to crash it on the maiden flight either. What and how would you folks handle this situation. TF does call for a .61-.90 size 2 stroke or a 70-91 four stroke. So either way I would be on the bottom of the spectrum. The plane now weights in at 11.2 lbs. As always thanks for your input.

chopper

Start with the 12-6

I don't post much here, but do read a bit, so I'll throw out an opinion just for what it's worth. It amazes me that Tower bundles that plane with a .61 FX. Yes, it will certainly fly it, but only in what could be describes as "in a scale manner." I remember back in the mid-80's, a flying buddy built a beautiful Cosmic Wind. It weighed over 12 pounds and was powered by an OS .61....probably an FSR. Once the plane was airborne and up to speed, it was smooth, groovy and very impressive. However, he had no excess power and the plane required relatively advanced skill to fly well. It was far beyond my skills at the time and I remember being very impressed at how easy he made it look. I guess the bottom line is the .61 in your Arrow will probably be pretty close to that Cosmic Wind. If your thumbs are up to the task, it will be OK, but you'll really learn the meaning of flying on the wing.

If it doesn't fly with the 12 X 6, you'll need a bigger engine

Thanks. I'll start with the 12X6 and see how willing it is to get off the ground. Is there a good rule of thumb to pushing the takeoff run before you know that it's just not safe to continue to try and get her airborne?

chopper

don't try to force it off the ground.

Be on pavement or short grass and see if it will fly off by itself

When you force one off they often roll over to the left in a cart wheel crash before they get 20' off the ground

Relax - its going to fly - It may not have an over abundance of power but it will fly just fine

That's good advice. I never really thought about it but when I fly my RV 4 I really don't lift it off the ground as much as it flies itself off the ground.
Thanks

chopper

That cartwheel crash is a result of the wing lifting the plane before you have complete rudder and aileron control of the plane

My TF Arrow weighs in at 15 lbs. with an OS .91 4-stroke/ flex pipe (OVER POWERED for my taste). I fly it scale at approx. 5/8 throttle in cruise.
It flies like a champ and super easy to fly with no surprises. With a moderate AOA I can maintain Alt. and a remarkably slow speed.

You will have no probs with the .61.

Some pics. There's more in my Gallery.

Thanks. Yours is a great looking bird. Nice job!! Here is a pic of mine. I didn't scale it out like yours. I'm saving my money for the Bonaza kit that I'm going to build.

chopper

Those are both very nice looking planes

Thank You.

Sweet job on yours... I like that you built the surfaces with corrugations (all 236 of them[X(]) and got the cowl flush with the fuse.

Yours is LIGHT compared to mine... Your .61 will not work hard to keep it flying.

Mine is 'heavy' with lights w/ batt, retracts, cockpit and small extras and flies very very well.

Be sure your engine is broken-in and well adjusted (needles) and CG'd properly before you maiden it. You'll have fun with that plane's performance.

Chopper', Be sure you have a "heat escape" in the cowl on the bottom at the firewall.... 2 strokers get hot, so relieve it's 'pain'.

BTW, The Bonanza is next in line on the build-bench... haven't decided to go 'V' tail or conventional yet.

I guess I'll need to open the bottom a little more. The only opening I have in the bottom is a space just wide enough for the fix nose gear rod and the exhaust extension. I'm definitely going with the V Tail on my Bonanza. I going to put all the lights on it along with the cockpit kit as well. I'll make sure that I have a big enough engine on this build. Like everything else you just can't replace experience. The Piper was my first build in 30 years so I've still have a big learning curve. Thanks for the compliment on my Piper along with all the great information. Hopefully I'll fly it Saturday.
Thanks

chopper

When it comes time for the Bonanza be sure and present it on here

I sure will. It's nice having all of your input. It's always a huge help.

chopper

Good luck today. I hope the WX in your area cooperates for a good maiden.

Let us know how it goes... Good luck, you'll do fine.