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Thomas, my set up will not produce 250 hp because I have the 2:17 drive. However, I still do have some hp to play with. I could sacrifice 10 hp and still leave the airport vertically. Power Sport claims 215 hp without ram air so I should do somewhat better than that. I will consider your suggestions tomorrow when I have the engine in front of me, but at first glance they look good. Some kind of double plenum will be required, the first one supplied by ram air and housing the air filter and the second plenum feeding the bell mouths. Jerry
On Sunday, April 17, 2005, at 05:07 PM, rijakits wrote:
Jerry,
the last time you posted a drawing of your proposed intake you had the ram air coming in right beside the airfilter.
Just make a box around all of the filter. Feed the ram air into this box and have the unfiltered air intake beside the filter. Have either of both intakes selected by a sliding plate. This way you have a chance to get unfiltered ram air ( in case of filter icing) or filtered ram air. You mentioned some times you only need 200 hp, but the way you seem to work your set-up, you will probably see some 250+hp, so why not sacrifice a couple of horses for the filtered air.
I am flying some 5000+ hours in front of filtered air only - with the choice of heated air or unheated, but always filtered.
Robinson goes the same approach as you - choose an engine with "too much" power and downrate it on the paper (Robinson Helicopter power limits are only limited by max manifold values published in the POH, but all available power is there when you need in an emergency and the airframe/transmission can take it as well for some time)
In your case you are at least 50 horses on the wild side of your needs, why not sacrifice a few for some clean air, no matter where!
You are in the lucky position to be able to produce a s$%&load more power than you need at the basically same engine weight.
In case you want to go for all filtered only you should have even more space for a bigger filter, but you might consider some way to supply heated air, just in case...
Thomas J.
----- Original Message -----
From: Jerry Hey
To: Rotary motors in aircraft
Sent: Sunday, April 17, 2005 3:55 PM
Subject: [FlyRotary] Re: Apex Seal Groove Wear and Air Filters was Re: [FlyRotary]...
On Sunday, April 17, 2005, at 03:41 PM, WRJJRS@aol.com wrote:
In a message dated 4/17/2005 9:27:23 AM Pacific Standard Time, jerryhey@earthlink.net writes:
Hi Leon. I am in complete agreement about the need for air filtration.
On one hand we have the need for filtered air and on the other we
want the performance boost from ram air. If we supply ram air to a
plenum and filter it before it enters the engine, is there a
significant performance hit? If so could the ram effect be regained by
using a larger filter, bigger scoop, and so on. I am building my
intake right now and it will have filtered air with the option of
switching to ram air at altitude. Do you think this is a good idea?
Certainly some dust exists even at 10,000 ft. Jerry
Jerry,
I'll be interested in Leon's take as well, but I wanted to kick in here. Yes you can ram air a filtered plenum. If you look at any of the newer motorcycles 600cc + you will find that all the sports and performance bikes use ram air, and the largest plemum box they can fit in the frame practically. There is a noticeable power increase that I tested on the track. Run the biggest filter you can fit in for the lowest pressure drop. I like the K&N oiled filter element.
Bill Jepson
Thanks Bill, looks like I have some redesigning to do. Jerry
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