Starter for my WWI fighter! (250 cid Ford with PSRU)

[Von Writter]

Hi All, I have a question on what starter to use on my 250. It is an engine that is going into my German WWI fighter replica (Fokker DVII) I want to use a light weight starter in it. I have a billet Aluminium flywheel on it with a 157 tooth ring gear on it. The mounting plate is the same as a drilling pattern off a splash shield on a 71 maveric automatic. Can I use just a regular Ford starter off a 302 or ??? Any help will be greatly appreciated!!!! As for the plane part of it, the engine is now in and if I knew how I'd post a picture of it here as this is a not so common use for a 250 [/img]

 

[Von Writter]

will this work for a picture?? [http://www.mykitplane.com/Planes/PeoplesPlanes/DVII%20Engine%20and%20PSRU%20002.jpg][/url]

 

[PutPut6]

Looks like a cool project, got any pictures of the plan?

 

[Asa]

search for posts by MustangSix about using an FE series mini-starter for his LoCost project

 

[saltwaterfalcon1960]

AWESOME!!! What a cool project.I love it.Please let us know when you get it done.Would love to see it finished.

 

[Anonymous]

I am using a "Big Bell" 200 with 164 tooth flexplate, but the number of teeth isn't as important as starter "nose" length. I use a stock Ford "lightweight" PMGR (permanent magnet gear reduction) starter from late 90's Fords.

Works great and is cheap ($20 from ebay)

 

[Anonymous]

Oh yeah, what is the PSRU reduction ratio?? A 250 is very torquey, and won't need to be reduced much.


Or....just swing a much bigger prop, slower.

 

[MustangSix]

You can use a 5.0 starter. The permanent magnet style is probably the lightest. You could also use any gear drive starter for a 5.0 automatic for a little more weight reduction.

Cool project!

 

[Von Writter]

Looks like a cool project, got any pictures of the plan?

Hey Thanks for putting the picture up! I still havn't figgured out how to do it! There are some more at My kitplanes. [http://www.mykitplane.com/Planes/PeoplesPlanes/Prop%20on%20015.JPG][/img][/url]

 

[Von Writter]

The PSRU is a 2.176/1 ratio, it will be swinging an enomous prop, 96X87, I have had the engine boared, statically and dynamically ballanced, an RV type cam put in, SS valves, port divider, heads ported and pollished etc... I'm not sure how much gross torque I'll be getting but hope for around 320 ft. Lb, at 3050 rpm. Is that a realistic expectation or ??? A picture of the prop can be found here http://www.mykitplane.com/Planes/People ... croped.jpg , My wife is holding it just for scale purposes.

Oh yeah, what is the PSRU reduction ratio?? A 250 is very torquey, and won't need to be reduced much.


Or....just swing a much bigger prop, slower.

 

[Von Writter]

You can use a 5.0 starter. The permanent magnet
style is probably the lightest. You could also use any gear drive starter for a 5.0 automatic for a little more weight reduction.

Cool project!

Hey Thanks for the help! I really appreciate it. I have a 157 tooth flywheel off a 5.0 so that makes sense. I just couldn't find any starter listed for a 157 tooth gear. If you want to see the engine in the fuselage, you can look here. http://www.mykitplane.com/Planes/People ... %20015.JPG
Thanks again to you and everyone for your help!
Troy W.

 

[Lazy JW]

... I'm not sure how much gross torque I'll be getting but hope for around 320 ft. Lb, at 3050 rpm. Is that a realistic expectation or ???

That will require a BMEP of over 190 psi. Not sure if that is attainable at that rpm with that head without a power adder.

Sure is a nice project 8)
Joe

 

[Lazy JW]

Wow! I just calculated the rim speed of an 8 foot diameter prop at 1400 rpm and it is over 35,000 fpm
Joe

 

[Von Writter]

Wow! I just calculated the rim speed of an 8 foot diameter prop at 1400 rpm and it is over 35,000 fpm
Joe

Yes that is 622ft/sec. But it is only 56% of Mach so it is OK as one can go up to .80% mach. BTW what did the abreviation in your other post mean as regards PSI?
Troy W.

 

[Lazy JW]

BMEP = Brake Mean Effective Pressure. It's a fancy term that engineers love to toss around but it just means the average amount of positive pressure that the pistons see. If you add up all the negative forces in the engine (compression, friction etc.) and then subtract that from the positive force (the power stroke), the result is BMEP. Nascar engines run over 190 psi BMEP. Tractor engines (gasoline) average about 100 psi, I'm guessing you will do well to hit 150 without some sort of supercharging.

We routinely run sawmill saws at about half that speed.
Joe

 

[Anonymous]

Flywheel teeth doesn't select a starter, you are thinking of Chevy

BTW what did the abreviation in your other post mean as regards PSI?

BMEP = Brake Mean Effective Pressure. And that number sounds too low.

Your crankshaft has throws....think of those as levers.
The face of a piston only has so much surface area.
You need enough pressure (on the surface)
to push down on the crank (force on the lever)
to create the amount of torque you need.

I think you should be able to hit 300 ft lbs with that 250, but at what exact RPM I can't say. You should go get it dynoed (highly recommended for an aircraft application) then you will know.

What will you do for carburetion/induction/fuel handling?

 

[Anonymous]

OOOPS..... JW and I are on at the same time....

The reason I feel that 190 psi sounds too low, is BMEP is the pressure a piston sees when the engine is running. 190 psi sounds like cranking pressure.

 

[PutPut6]

You should turbo it!

 

[Von Writter]

Flywheel teeth doesn't select a starter, you are thinking of Chevy

BTW what did the abreviation in your other post mean as regards PSI?

BMEP = Brake Mean Effective Pressure. And that number sounds too low.

Your crankshaft has throws....think of those as levers.
The face of a piston only has so much surface area.
You need enough pressure (on the surface)
to push down on the crank (force on the lever)
to create the amount of torque you need.

Power requirements for an aircraft engine that is scaled down is done on the cube root. So I have a NASA Engineer friend who says that I'll need 460ish ft lb Torque to spin that prop so if I can get around 280-300 'lb, I'll be very happy. I chose the IL6 Ford because my DVII used a Mercedes in-line 6 (900cid) and as we all know, Ford makes a good engine!)

For a carb, I'm using a Zenith side draft which will be fed by a plenum box located in a high pressure area behind the prop.

What will you do for carburetion/induction/fuel handling?

 

[Von Writter]

Flywheel teeth doesn't select a starter, you are thinking of Chevy

BTW what did the abreviation in your other post mean as regards PSI?

Power requirements for an aircraft engine that is scaled down is done on the cube root. So I have a NASA Engineer friend who says that I'll need 460ish ft lb Torque to spin that prop so if I can get around 280-300 'lb, I'll be very happy. I chose the IL6 Ford because my DVII used a Mercedes in-line 6 (900cid) and as we all know, Ford makes a good engine!)

Just to clarify, The 280-300 number is before it goes through the PSRU. After it comes out the other end the torque is multiplied to 610-652 ft/lbs torque!! The original BMW (stronger than the big M) made 750ft/lb torque which scaled down to 90% is around 504ft/lb torque. If I have more power than I need I'll just be able to grab altitude quicker and hang on the prop better.
TW