TruBlu02

Hey guys I am fairly new to speed planes as I have been a 3D and sport flyer for a long time. I am in the planning stages of building a SPAD sickle. For those of you not familiar with SPAD building check out www.spadtothebone.com. I attached a sample pic of what I am building. The motor I plan on using is a fairly new TT pro .46. My problem is I have absolutely no idea where to prop this thing at. I'm planning on upgrading the bearings in the engine and using a tuned pipe as well. I expecting in excess of 16K rpm's with this set up. Like I said Im mostly a 3D guy so this style of flyig is new to me. I appreciate anyhelp you guys can give.

Razor-RCU

My Feedback: (50)

I would run a 9x7 for starters...Wait how big is this thing?

The Jett Stream and Ultra-Thrust will give you 1200+ RPM's but they are not cheap- the Tower muffler will give you maybe 600 for $15-

TruBlu02

Wingspan is looking to be 44 inches. I am scaling up the plans 10% from original to compensate for the bigger engine. As for Pipes I was looking at the MAC pipe on Tower for $70 or so bucks. Has anyone used that one on the Pro .46?

Mike Connor

My Feedback: (5)

A 9 x 7 prop would be a good starting point and you should get around 17,000 rpm with a tuned exhaust. i would go with the Jett or UT tuned muffler rather then a pipe. It looks like a pipe would stick out well to the rear of the aircraft.

TruBlu02

thanks for the advice. I think I may try the tower muffler first and seehow that works out. I forgot to mention earlier that I just got a couple new APC props from tower. I got a 9x8 and a 8x9. I will also pick up a 9x7 as well. Hopefully somewhere in there I can find what I am looking for.

vicman

My Feedback: (10)

I second the 9X7. I get 16.5-17K on the stock muffler. Go with the Jett from the start and don't waste time or money. Don't try to go over 17K till you change the bearing. If you start smoking plugs you need to prop up or at least get the bearing cause it's getting ready to go.

Razor-RCU

My Feedback: (50)

Well there you have it...Pretty specific advice from a Revver who races, another who is a designer and doppler-guy and yet a 3rd that just guesses (me).

Good luck!

TruBlu02

Thanks for the advice guys. I cant imagine what this TT is going to sound like at 16-17K. I am probably going to start out with the stock muffler. Should I remove the baffle or leave it in there? Should be fun.

vicman

My Feedback: (10)

Leave it in. It won't make much diffrence. Mine are a little easier to start with them in.
You will want to change the drawbolt that holds it togeather tho. I use 6-32 threaded rod with a jam and nyloc nut on both ends. I also run a film of JB weld around the joint.
The stock drawbolt will break in a fairly short time.

bob27s

My Feedback: (19)

No need to remove the baffle....

Down the road, if you want to improve performance, bolt on a jett-stream muffler and your smile will grow larger.