A mod idea for "A"s

Bob Axsom · #1 11-03-2007, 04:41 PM

The hole in the top of the nose wheel fairing around the strut is bothersome to me from a drag perspective. It either lets air in from the top to cause drag or it provide a flow path through the fairing that causes drag. I plan to develop an aluminum and rubber seal to close the gap. has anyone else done this? If so what were the results?

Bob Axsom

Captain_John · #2 11-03-2007, 04:49 PM

Oooooh, I got this one!

It's my turn!

Get rid of the nosewheel!

Pitch it in nice and slow like that and SOMEONE is BOUND to hit is outta the park!

Sorry Bob, I am just in that kinda mood.

Now, back to your regularly scheduled programming.

CJ

hevansrv7a · #3 11-03-2007, 05:19 PM

link to picture
This is an in-progress picture of how I used the piece from Fairings Etc. on my Sam James nose wheel fairing. It's done and painted, but this shows it best. The finished version has more filler around the sides, closer to the leg fairing but allowing full turn left/right. I have no before-after data, but I was thinking about the same problem. I'm not sure an air seal would make much difference, but I "intuitively" felt that I wanted a smoother change in airflow direction from the wheel fairing to the leg fairing.

db1yg · #4 11-03-2007, 05:55 PM

Here is what I did.

Cheers,

db

GrayHawk · #5 11-03-2007, 08:25 PM

Quote:

Originally Posted by Captain_John

Oooooh, I got this one!

It's my turn!

Get rid of the nosewheel!

Pitch it in nice and slow like that and SOMEONE is BOUND to hit is outta the park!

Sorry Bob, I am just in that kinda mood.

Now, back to your regularly scheduled programming.

CJ

Naaaah!

All that does is move the drag farther aft.

Captain_John · #6 11-03-2007, 08:49 PM

That's a yaw damper!

CJ

Bob Axsom · #7 11-03-2007, 08:57 PM

No respect. My wife and I went out to celebrate my 71st birthday anniversary and I come back to this. HA Ha - clever actually. The real inputs look good. You both were probably smarter than me and put this in your original build sequence so no before and after data. My idea is to sandwich 1/16" rubber between the inside of the fairing and an aluminum back plate. I will pick up two existing attach points at the fairing joint and add one in front of the strut. The rubber will make intimate contact with the strut all around. Tom Martin (EVO Rocket) of Ontario (Canada not California) has told me about the advantage of bridging the gap between the faring and the tire with rubber and I plan on having that in place by the Rocket 100 in Taylor, Texas on the 17th of November as well. My bench mark now in 177.8 kts at 6,000ft density altitude, WOT, max rpm (2700+), etc. I would like to get two tests in before the trip down to Taylor - one with the top hole sealed and one with the bottom gaps also closed.

Bob Axsom

Rivethead · #8 11-03-2007, 09:08 PM

Call Wally at Synergy Air and ask him about his mod. Very simple and works like a charm.

pierre smith · #9 11-04-2007, 06:26 AM

Bob,
Since you're so ambitious, consider making doors that cover the wheelpants after takeoff. An engineer named Nick Jones made two pairs for his Cassutt wheelpants back in the seventies, for the Reno air races. The doors would be beside the lower part of the wheelpants in the "gear down" mode and after takeoff, he'd lower the doors and completely cover the exposed tires. The mechanism was an X with the two parts of the X pivoting in the center. One in front of and one behind the tire inside the wheelpants and one side pulled by a cable to the cockpit. He figured that if he ever forgot to "lower" ther gear, he'd just slide in on the closed doors and wear them out landing.

Other racers used brush bristle bonded to the inside of the wheelpants that rubbed the tires and kept air from swirling around down there. They also gap sealed all control surfaces in a similar way.

If you're interested in the doors, I'll contact him for you.

Pierre

hevansrv7a · #10 11-04-2007, 06:44 AM

In a conversation with Sam James he recommended putting in an air dam aft of the tire, shaped the same as the curve of the tire and quite close to it. It would be like a bicycle fender. This is instead of the flat, vertical air dam I have in mine. He said this was a popular idea at air races. Perhaps everyone but me already knew this, but just to be helpful..