low pressure area inside APS body

[sofadriver]

Ive built an APS body that Im really happy with. Almost no air gets in except a little around the fork trees (theres an inner fenderwell that you cant see in the pics).
Now Im wondering if Ive created a low pressure area inside that could affect performance.  ( bike is carburated.)
What do you think?

[wobblywalrus]

The pictures do not come up into view.

[sofadriver]

Thanks
New smartphone.
Trying to figure this thing out.

[sofadriver]

OK, I give up on the pics. (What good is this Dropbox app if you can't post pictures with it?  )

So, I'll offer this hypothetical question instead;

If a streamliner was built with almost no air entering the body from the front or sides and the tail was chopped off leaving a large opening, could that cause a low pressure area inside the body that's bad enough to affect the performance of a carbureted engine? Assume a speed of 120mph.

Thanks

[TheBaron]

Yes, it is very possible.....

A simple water manometer can show you  the local pressure in the carb air inlet area when at speed....

The trick to a proper reading is having a good "static" reference...

Lookup static ports on small aircraft to get an idea of how to do it....

Good luck with your fairing,
Robert

[Koncretekid]

My APS fairing is shown as follows:  The 3" diameter inlet only supplies cooling air to a shroud around the motor and is exhausted out the left side so does not supply any air to the inside of the fairing.  The two smaller 1-1/2" diameter holes were intended to supply ram air to carbs but never hooked up.  The holes around the fork tubes look large, but the forks just clear the fairing at full lock (10-12 degrees each way). I had no problem with air supply to my motor at 145 mph, but with only 45 hp.

There is so much open space with an APS fairing, I don't think you can create a negative pressure within, especially back at your carburetion area.

Tom

[SPARKY]

Nebulous  thought  rig up the manometer and use a big floor fan or leaf blower

[JimL]

I have been running closed APS fairing for several years.  It works fine.

You will have more trouble from velocity stack clearance/separation hurting the top end power.  Anything too close to a stack, even beside it, can be trouble.  If your stacks fit in nice and neat and snug.....its bad.

It really keeps the salt out...I like that.  Also, I run a full skirted internal rear fender, inside the tailpiece...more help with that salt.

[sofadriver]

"There is so much open space with an APS fairing, I don't think you can create a negative pressure within, especially back at your carburetion area."
--Thank you, Koncretekid ........I probably worry too much about this kind of stuff.  BTW, is that Rustoleum Safety Yellow? My paint and color of choice, too. $26/gallon and I've got a 1/2 gal of touch-up paint left! Gotta love it.


"You will have more trouble from velocity stack clearance/separation hurting the top end power.  Anything too close to a stack, even beside it, can be trouble.  If your stacks fit in nice and neat and snug.....its bad."
-- Thank you, JimL. Thats good advice that I will keep in mind.


Still cant post those pics  :x

[Koncretekid]

"BTW, is that Rustoleum Safety Yellow?"

It's a Limco automotive color, but I don't remember the name or number.  Let's just call it "Fast Yellow".

[Sumner]

"BTW, is that Rustoleum Safety Yellow?"

It's a Limco automotive color, but I don't remember the name or number.  Let's just call it "Fast Yellow".

We used Limco from these guys...

http://www.thepaintersedge.com/categories/paint/mixed-paint.html

.... last summer on the mods to the Stude and I was happy with the paint, just not ....


http://purplesagetradingpost.com/sumner/Hooley%202013/13%20-%20construction%20menu.html

...the painter (me).  If it looks like we were all about half asleep it was because it was about 1 am and we should of already been on the salt a day and a half before the picture was taken  

The Limco from them was about the cheapest custom mix paint I could find and Hooley deserves nothing but the cheapest  8-),

Sum

[sofadriver]

 Ha - thats why I used an oil based paint and a roller. I always have an excuse for the mediocre paint job. 

[sofadriver]

one more try

[Sumner]

Now that is nice.  Good work,

Sumner

[sofadriver]

Thank you, Sumner.

And that's just the first coat of Rustoleum!  :lol: :lol: :lol:
(No way I'm going to let that fiberglass get rusty! )

I was just looking at your impressive site. Very nice!! And the Stude is awesome!!
Were you connected with the Purple Sage store in Las Vegas? Bought my first house right around the corner back in 1974.