REFLECTOR: Franklin Will not turnover when hot

[Laurence Coen]

Rene',

I have three ram air scoops on the lower cowling.  Two armpit and one belly.  The armpit scoops are plumbed to the split plenum on the top of the engine.  without the belly scoop cool air would pass over the cylinders and exhaust manifold and fill the cowl with hot air that would then exit the rear of the cowl.  Good for the cylinders and bad for everything else aft of the firewall.  The belly scoop hides the carburetor air box and supplies cool air for the fuel pump, alternator, magnetos, gascolator, ect.  The oil pan on the Franklin is fined cast aluminum (heat exchanger) and also wants cool air.  Every installation I am familiar with has a positive pressure in the cowl, not a vacuum.  I too have a "wimpy" scoop for engine air but it is hidden by the cooling scoop.  The belly scoop is extended away from the cowl to move it out of the barrier layer.

I hope this clears things up for you.  If you have any more questions just jump back in.

Larry Coen
N136LC


From: Rene Dugas 
Sent: Wednesday, June 01, 2011 5:46 PM
To: 'Velocity Aircraft Owners and Builders list' 
Subject: Re: REFLECTOR: Franklin Will not turnover when hot


Larry,

I may not be understanding this note but if you extended the scoop is there just more space or are you blowing air from the scoop over the pan and accessory case.  This cooling air is coming from where?

If it opens under the engine, I do not see how you obtain the cowl vacuum we all want for downdraft cooling.  I must be missing something.  Help?  I like the scoop.  Mine is whimpy in comparison so please be gentle but I get 1" of increased manifold pressure.  What do you do with all that air?

Rene'

 

From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On Behalf Of Laurence Coen
Sent: Friday, May 27, 2011 1:13 PM
To: Velocity Aircraft Owners and Builders list
Subject: Re: REFLECTOR: Franklin Will not turnover when hot

 

Mike & WJ,

 

My brother made two starter nose pieces, the first of which is shown in the photos.  The recess where the mounting bolts go are machined on the wrong side.  Number two is in use.  I think that your hot start problems are related to heat soaking the starter motor and the reason for the third picture.  My belly scoop is extended down 1" to increase air flow over the oil sump and the accessory case.  I wasn't so concerned about the starter but the alternator getting too hot.  I have #2 wire and never a hot start problem.  A plenum mounted blast tube for the starter might be the solution.

 

Mike.  You may be able to use my "spare" nose piece if you trim off the mounting ears and add an "L" shaped bracket to clamp the starter in place.  If you want it email me off reflector with your address and I'll send it to you.

 

Larry Coen

N136LC

 

P.S.: My brother is retired and no longer has access to a machine shop.

 

 

From: Michael Watson 

Sent: Sunday, May 22, 2011 5:13 PM

To: Velocity Aircraft Owners and Builders list 

Subject: Re: REFLECTOR: Franklin Will not turnover when hot

 

Larry,

Mine came with the same starter and adapter plate. I replaced the original starter with a skytex and then a ford (NAPA 2446115),
but still the same problem. I have never had a problem with adapter plate, but you are right, it is poorly made and is
prone to leak oil back into the starter solenoid. Would your brother consider making one for me? PM me if he can.

  

On Sun, May 22, 2011 at 3:13 PM, Laurence Coen <lwcoen at hotmail.com> wrote:

Mike,

 

My Franklin came with a Honda Civic starter with a very poorly made, welded-up adapter plate.  Luckily my brother was a tool and die maker and produced an adapter of my design from an aluminum billet.  The battery is a 55 AHR Optima deep discharge with #2 wire.  Never a starting problem.

 

Larry Coen

N136LC

 

From: Michael Watson 

Sent: Wednesday, May 18, 2011 3:38 PM

To: Reflector 

Subject: REFLECTOR: Franklin Will not turnover when hot

 

To all Franklin powered Velocity owners.