Airflow Performance FM-200 Air Inlet

[DanH]

Originally Posted by Mark Dickens

The air box I used was the Spectre Performance 9833: http://www.spectreperformance.com/se...aspx?prod=9833
The best info I could find (and I'm not sure how good this is) says that the filter provides 450 CFM...seems a bit optimistic, but according to the calcs, my engine would require about 289 CFM at 2700 RPM,

CFM without a pressure loss value means zip. That cone filter doesn't have enough media area for low restriction.

Been there, done that.

http://www.vansairforce.com/communit...92&postcount=9

This one did have enough media area. Start at post 11:

http://www.vansairforce.com/communit...t=44856&page=2

[scsmith]

Originally Posted by DanH

The least complicated approach is to modify the lower end of the snorkel so it slips onto the FM200, and add a bump/blister to the lower cowl, in front of the FM200, for good clearance.

It's been done before...search is your friend.

Thinking out of the box, assuming your FM200 is new, Don at Airflow might work out a swap deal for an FM150, which is the same length as an RSA-5, and has the same flanges. It will cost you a bit less than 0.5" hg MP.

Dan, did you mean to say that the switch from FM200 to FM150 would cost 1/2" of MAP? Or did you mean that the snorkel installation through a filter would cost 1/2" of MAP relative to ram air?

[N661DJ]

Ron,
I just finished mine, AFP200 on an RV8, IO-390. I can't seem to figure out how to post photos, If you PM me with an email address, I will email you photos.
Dick

[DanH]

Originally Posted by scsmith

Dan, did you mean to say that the switch from FM200 to FM150 would cost 1/2" of MAP? Or did you mean that the snorkel installation through a filter would cost 1/2" of MAP relative to ram air?

FM200 to FM150, but I spoke hastily, and should clarify.

While researching a Kitplanes article, I asked Don Rivera to run a number of different fuel controllers on the Superflow bench. Here are the numbers, as published:

Airflow was set at 1560 pounds
of air per hour, an approximation of
a 540 Lycoming running 2700 rpm
on a 70?F day at Reno. The numbers
below represent carb loss in inches of
water?the loss of manifold pressure
due to intake restriction. Each control
was fitted with a standard intake bell
mouth before measurement.

RSA-5 12.75 inches
FM-150 10.0 inches
FM-200 4.0 inches
RSA-10 4.9 inches
FM-300A 2.6 inches

So, at 1560 lbs per minute, the difference between an FM150 and an FM200 was 6" H2O, or 0.44132" Hg. That's the hasty part; I didn't recall the flow rate. Obviously the loss would be a bit less with a 360. For our purposes here, lets assume 2/3's of 0.44, or about 0.3" Hg

[scsmith]

Originally Posted by DanH

FM200 to FM150, but I spoke hastily, and should clarify.

While researching a Kitplanes article, I asked Don Rivera to run a number of different fuel controllers on the Superflow bench. Here are the numbers, as published:

Airflow was set at 1560 pounds
of air per hour, an approximation of
a 540 Lycoming running 2700 rpm
on a 70?F day at Reno. The numbers
below represent carb loss in inches of
water?the loss of manifold pressure
due to intake restriction. Each control
was fitted with a standard intake bell
mouth before measurement.

RSA-5 12.75 inches
FM-150 10.0 inches
FM-200 4.0 inches
RSA-10 4.9 inches
FM-300A 2.6 inches

So, at 1560 lbs per minute, the difference between an FM150 and an FM200 was 6" H2O, or 0.44132" Hg. That's the hasty part; I didn't recall the flow rate. Obviously the loss would be a bit less with a 360. For our purposes here, lets assume 2/3's of 0.44, or about 0.3" Hg

Thanks! this is fantastic data to have. Working with Bob Mills, he has a RSA-5 on his moderately souped up IO-540. This will definitely help him decide what his options are.

[DanH]

Originally Posted by scsmith

Thanks! this is fantastic data to have. Working with Bob Mills, he has a RSA-5 on his moderately souped up IO-540. This will definitely help him decide what his options are.

Bob is not a Kitplanes subscriber?

Shame, shame....look what you're missing!

[rvmills]

Originally Posted by DanH

Bob is not a Kitplanes subscriber?

Shame, shame....look what you're missing!

Bob just needs to juggle less and read more! Steve's pinging me on the side, as I fly people and peanuts from place to place...he always has my back! So the 10.15" delta from RSA-5 to FM-300A equates to about .75" of MP? My old ram air did that, and it was consistently worth 3 mph (multiple tests and races showed it, and that matches the rule of thumb I was taught...1" MP = 4 mph...YMMV). The follow-on James inlet produced similar results, even filtered, likely attributable to better cowl inlet shape (thanks Steve!). I've had my eye on the FM-300 for a while...now that the engine is off for a mount repair, I may not have an excuse left. May try an internal plenum experiment to see if I can better the .75". One friend said I couldn't add horsepower via a mount change, and I said "watch me". Guess I better step up!

Steve and I were looking at the AFP site and trying to verify that the 300A is the non-purge valve version. Is that correct Dan?

Thx...great info as always!

Cheers,
Bob

[Weasel]

Originally Posted by DanH

FM200 to FM150, but I spoke hastily, and should clarify.

While researching a Kitplanes article, I asked Don Rivera to run a number of different fuel controllers on the Superflow bench. Here are the numbers, as published:

Airflow was set at 1560 pounds
of air per hour, an approximation of
a 540 Lycoming running 2700 rpm
on a 70?F day at Reno. The numbers
below represent carb loss in inches of
water?the loss of manifold pressure
due to intake restriction. Each control
was fitted with a standard intake bell
mouth before measurement.

RSA-5 12.75 inches
FM-150 10.0 inches
FM-200 4.0 inches
RSA-10 4.9 inches
FM-300A 2.6 inches

So, at 1560 lbs per minute, the difference between an FM150 and an FM200 was 6" H2O, or 0.44132" Hg. That's the hasty part; I didn't recall the flow rate. Obviously the loss would be a bit less with a 360. For our purposes here, lets assume 2/3's of 0.44, or about 0.3" Hg

Pressure squares with flow so if you reduce the flow by 2/3 (66%), the delta pressure will change to the square of the amount changed.

So while the flow between the two engines is assumed to change by 66% the pressure drop between the 2 engines would be 43% resulting in ~2.6136" H2O or 0.1922" Hg.

[DanH]

Originally Posted by rvmills

So the 10.15" delta from RSA-5 to FM-300A equates to about .75" of MP?

Yes, approximately.

May try an internal plenum experiment to see if I can better the .75".

...which will vary with altitude, temperature and velocity, so be sure to compare apples. If we assume 5150 (Stead +100) altitude, 70F local, normal baro, and 230 KTAS, available Q would be 2.05" Hg. Yes, there is some room for improvement.

Is 230 about right, and how many RPM?

Steve and I were looking at the AFP site and trying to verify that the 300A is the non-purge valve version. Is that correct Dan?

Ask Don. I suspect you can have it either way, drum or disk mixture valve. Disk valve units have a lower leak rate in idle cutoff, thus in theory don't need a purge valve...the real purpose of which is to bleed drum valve leakage back to a tank rather than into the engine.

[Weasel]

Originally Posted by rvmills

So the 10.15" delta from RSA-5 to FM-300A equates to about .75" of MP?

Negative. If you assume the reduced flow from a 540 (where the test data was collected) to the 360. You have 66% of the air flow. At 66% of the air flow the pressure drop through the fuel controller will be 43.6% so the pressure differential from the RSA-5 to the FM-300A when installed on a 360 running at 2700RPM is 4.4356 inches w.c. or ~ 0.325 inches Hg.

EDIT: OH! hey Bob. Nevermind. Yes .75" Hg. is correct for your application. I didn't think about you running a 540 :grin: