RCAIR-BAM

Tom:
Glad to see things are hopping for you.
Has anyone you know of put a 3w-100 in the 35% Giles? I moved the firewall back 2" to have the backplate sit close to the cowl and I'm going to bolt and epoxy the firewall in with angle brackets. This is going to be one Hell of a 3-d machine with plenty off power... Most likely have to put the rudder servo in the back to balance but we will see.

Kevin Gabelmann

Yak_54_flyer

My Feedback: (2)

Hey Kevin

I flew mine for a while before selling it with a BME 102. It was a blast to fly and had more than enough for anything 3-D. The only thing you might want to do to save later headaches is go to a heavy duty tail like a haigh style. They last alot longer. Your 3W-1O0 should pull it around very easy. The one I had weighed in at 22 lbs before 32oz of fuel. I had it balanced 3/8 inch in front of the tube, it would slow down nicely for landings.

Eddie Bernaldez

rctom

FYI the latest batch has some changes which included moving the firewall back enough to accomodate the 3w 106.

TF

Tired Old Man

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I'm sure happy to hear it flew well and slowed down for landings. Especially since I just mounted a Brison 104cc in mine.

With the larger engine, did you have to mount the rudder servo(s) in the tail?

RCAIR-BAM

Tom:
I have 1 from the first or second batch. It does not have the cut out on bottom for the pipes like one of my other ones did. I had to cut the firewall back almost 2" to get the right fit. I'm finishing the firewall tonight and should have the motor mounted this week. with so little that I have to put together maybe in two weeks it might be out.
Kevin Gabelmann

Yak_54_flyer

My Feedback: (2)

I'm actually thinking about getting another 202 if I don't buy one of the new 97inch extra specials. If I get one I will put a BME 105 in it. The one I sold to a buddy here had the best landing characteristics. It would settle in nicely, even with the tight area we have here in Longview. He actually just bought another 202 from Tom and I am waiting to test fly it next week. We balanced it in the same spot. Both my 35% Wild hare Extra have been the best flying planes I have owned in long time. I have one through a full season of IMAC and am still learning its flying traits. Just finally got my second one going with about 10 flights on it now. I actually found the 202 easier to hover than the extra though not by much.


Eddie Bernaldez

Yak_54_flyer

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The rudder servo was mounted at the back of cabin under the pilot. Just about in line with the rear hold screws. The elevator servos were in the tail. I started at 1 inch in front of the tube like the instrucions call for, but a little nose heavy for me. I finally placed the CG at 3/8 in front of the tube. Even there the plane didnt feel real pitchy. It was comfortable flying. For you guys considering twin cylinders really think about placing a baffle across the cowl about the middle of both cylinders to force air around the back. Tom told me about this and I never had a overheating problem once.

Eddie

Tired Old Man

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Brison suggests the same thing for all his twins. It's supposed to keep the air flowing through the cylinders instead of around them. If I knew what the cowl was laminated with I would laminate a baffle in place. I'd only be guessing between a polyester or epoxy laminate. You can't do polyester over epoxy. It doesn't bond. I'm not sure about the other way around.

Thank you for the info on the c/g and servo placement. It looks like a great plane on the bench, so hearing that it's a great plane in the air too is urging me to get mine done.

Pat

Yak_54_flyer

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Pat

Its easier just to use a piece of cardboard that measures across the cowl where you are going to place it. Keep trimming until you get the fit you want, then CA in place. I used pieces of 1/2 inch triangle stock cut in 1/4 pieces and put about 4 or 5 across the back of the plenum. I then painted the fron and back with fuel proof paint. Remember to get it as close as you can to the engine, I had about 1/8 clearance all the way across.

The cardboard is used just as a template. I used a piece of 1/8 inch thick balsa for the actual plenum.


Eddie

RCAIR-BAM

Pat / Eddie:
I use tag board to make my template for the baffles in the cowl then use 1/16" balsa for the baffle. I first CA in place then epoxy with glass on the back side. I have some pics if I can find them later.

Kevin

RCAIR-BAM

One more and the most important. Duh

Yak_54_flyer

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Looks great



Eddie

Tired Old Man

My Feedback: (1)

Thanks Kevin.

One thing's for certain, that's about as directional as you can get!

Pat

Yak_54_flyer

My Feedback: (2)

Just make sure that you have a plenum to stop and redirect the air to go behind and around the back of the cylinders. Making sure the rear stay cool too.


Eddie

RCAIR-BAM

Eddie:
Never seen anyone put a plate in to direct the air down across the back of the head. IMO you would be stopping the air flow by creating a backpressure and the air would look for an area with lower back pressure. With the baffle as shown the air will go over the head and fins. I have not had or seen any over heating problems with this install.
Engine installed this weekend.






Kevin

RCAIR-BAM

one more

Yak_54_flyer

My Feedback: (2)

Kevin

It doesnt stop and create any kind of low pressure behind it. It allows the air to be slowed down and go around to the back of engine. A flyer here had a fox 4.8 on his and had baffled the front air entry but still burned his engine on the third flight. Tom actually is who advised on placing the plenum where I did. We have done it to two more G202's here and have ahd great results. But I know this is probably only one of several ways to baffle, but it has worked for us. Keep your eyes peeled on the top of cowl for discoloration and softness after your first flight. If it feels soft, or for us the yellow actually discolored and was darker.

Good Luck
Eddie

Tired Old Man

My Feedback: (1)

Eddie,

Would it be possible to post a pic of one of the baffle/plenum installations? I think I understand what you're talking about, but a picture is worth a thousand words. Thanks if you can.

Pat

Yak_54_flyer

My Feedback: (2)

Pat

I would have to get a picture from the now owner of the Giles. I sold it about 2 months ago. I will try.


Eddie

Tired Old Man

My Feedback: (1)

Thanks, Eddie, I understand.

Let me run this by you then to see if I have it correct. Essentially, from across the mid point of the cylinders, at both the top and the bottom of the engine, I need to install a baffle that forces the air through the cylinders and exits down and out the aft bottom of the cowl. A 1/8" clearance is acceptable. Does that pretty much have it?

Pat

rctom

The terminology may be what's confusing.

On the Giles the cowl air entry holes are at the top of the cowl, above the cylinders. If installed as is with a hole in the bottom rear of the cowl to exhaust hot air, the natural path is over the top of the engine and down the back, missing the cylinders altogether.

A small barrier glued across the top inside of the cowl will prevent this, and air will naturally flow across the cylinders. Balsa wood or lite ply will do it.

TF

Tired Old Man

My Feedback: (1)

Tom

Thanks for the clarification. If you haven't noticed, I'm finally getting around to getting the Giles together after scrounging all the other associated parts and systems needed to completed it. Excellent parts fit and alignments so far, with all the incidences extremely close to zero. Darn good for an ARF!

Pat

RCAIR-BAM

I'm planning on making the baffle this weekend and like Tom say the Giles is alot different than an extra it takes a little different planning. I will post a pick when I get done.
I'm thinking a big chamber with a smaller outlet that makes the air pass through the fins. We will see how the flow looks with some test tag board. Things may change....

Kevin

rctom

Rule of thumb is the outolet should have 3 times the area of the inlet to get good flow.

TF

RCAIR-BAM

Tom:
Yes I know on the bottom of the cowl. I'm talking about going past the head. The problem is that the engine sits so far back and also the shape and design of the giles cowl. To many places for the air to bypass the cooling fins. Not really designed to be a model as far as that intake goes but it's scale right. LOL

Kevin