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Firewall Forward Weight

PostPosted: Thu Aug 19, 2004 10:15 am
by Sean_Caranna
What is the firewall forward weight for a Zenair 601 install? how many more lbs for a 95c.i. engine?

PostPosted: Fri Aug 20, 2004 12:59 am
by Brett
We have the weight at 208 lbs. right now installed. The 95ci. is the same weight. Unless you want the bigger starter. That weighs about 4 lbs more.
We are doing some other things that should get the installed weight down to around 190 lbs. very soon.

Twin Cam for Volksplane VP-2 or Sonex

PostPosted: Fri Sep 03, 2004 9:23 pm
by Sean_Caranna

Because of how narrow the twin cam engine is I would imagine you could keep the engine mounted very far aft (close to the firewall) in an installation. This attribute would seem to make it a candidate to power my VP-2 or a Sonex.

I spoke to sonex a while back about using a corvair setup. They are opposed to this because they feel that you can’t get the total firewall fwd weight under 200 lb including the prop, cowl, etc.

Del Magsam has a corvair powered Sonex that by all reports flys great. Del has the firewall fwd weight at or just over 200 lbs and has done quite a bit to move as much weight as possible aft by mounting the engine close to the firewall and using a rear starter setup. See pics below…



I’m not so sure that they try to steer builders away from other engines for any sound engineering reasons or because they sell the Jabiru and Aero-Vee engines that they do recommend. Sonex has even removed Del from their completions web page.

A Volksplane using a TC-88 may be an option if the weight can be kept aft like Del has done on his corvair. There are a few corvair powered Volksplanes out there. What do you think of this type of installation for your engine?


Sean C. Caranna

PostPosted: Sun Sep 05, 2004 11:44 pm
by Brett
Your right about keeping the weight close to the firewall if you need to. On the 601 we have about 5 in. of open space between the fire wall and the engine. That is where it needed to go for W&B. It would work great on a Sonex. You are right they don't even want to talk to you if you don't use one of their motors.