Jett for Mach-1?
 

Hi guys,

I am gathering parts for a re-created Midwest Mach 1 (see thread over on classic pattern). Was thinking about some of the old school pattern engines that are still available like the Webra Speed and Rossi 60s. Then stumbled across Jett .. I am intrigued by your motors! Looks like a SJ-90 or the BSE equivalent is about right .. need to turn an 11-7 (ish) prop at 12K RPM at least .. looks like your motor would do another 2-3K over that.

One thing about the Mach-1 was always a limited fuel capacity, can you give me WOT fuel consumption estimates for the Jett 90 with this prop? Or at least some typical tank size/flight duration data? Heard of any other customers with this airplane?

Thanks a lot .. looks like you have a terrific support forum here...

Dave McQ

RE: Jett for Mach-1?
 

Hi Dave...

Thanks for writing, and sorry for the delay.

A Mach 1 with a SJ-90LX up front would reallllllly move. That thing will turn an 11x7 up well over 15,000.

I owned a Mach 1 a friend built for me many years ago. Outstanding airplane, at the time powered by an OS 61 FSR.

But keep in mind, the Mach 1 was design around the "old" .61 size engines. Before even the Rossi and webra speed. It used a Webra blackhead, ST bluehead, OS goldhead, Veco/K&B .61 ...... all of those engines were physically smaller and about 1 oz ligher than todays OS61FX and probably 2oz lighter than the Rossi 60.

So, considering that, plus as you noted there is not much room in there for fuel, let me suggest the following.....

Look toward a Jett 60L with a side exhaust pipe (Full size pipe instead of the jett-stream muffler). This can be tuned slightly longer, set up for around 14,000 peak ground rpm with an 11x6 prop you will have all the power you ever wanted when it unloads in flight. Very user friendly engine, throttle and transition are great, and idle is wonderful. PLUS ...... the 60L is a "40" size engine, and is only about 18 oz including a header and pipe. It will fit better, weighs about 3oz less than a "big block". Don't let the 11x6 scare you.. the key is propping the engine and airplane combination effectivly.

Alternately....
Consider an OS55AX engine, combined with a jett-stream muffler. Use an 11x6 prop here too. Outstanding, very simple combination. Quite a few are flying, and they are a perfect choice for the older pattern planes, like the Mach 1 - Intruder (original) - Eyeball - Taurus ... that use to use the smaller .61 engines.

For a great example, look up the thread on the AKM F-16 build in the Extreme Speed forum. That plane normally would have a .61 or 91 size engine up front, he went the "light" approach with the OS/Jett combination. Worked out great on a bigggg somewhat draggy bird.

Let me know how the project works out!

Bob Brassell