H9's Sundowner

[CRG]

Is it just me that thinks 50cc in this airplane is kinda nuts? Not that I don't encourage experimentation, but it's only 80" span. Have been flying mine on a Saito 1.80, weight is around 10.75 lbs. and it flies awesome. As fast or faster than the EVO 35 powered version and handles much better.

CG.

[Flatlandman]

I flew my buds with the da50 for every flight its had and it flew great there are no ill effects to flying this with a 50 as far as flight performance is concerned. Plus you can attain a lot more speed out of a 50; thats what I'm going for and i believe that maximizing speed is what Mfuess is going for also.

[mfuess]

	Quote: Originally Posted by Flatlandman
	I flew my buds with the da50 for every flight its had and it flew great there are no ill effects to flying this with a 50 as far as flight performance is concerned. Plus you can attain a lot more speed out of a 50; thats what I'm going for and i believe that maximizing speed is what Mfuess is going for also.

That would be correct Mr. Flatlandman. My BME-50 weighs 2 ounces LESS than an Evolution 35. I can sling a larger prop at a higher RPM. I like Moki engines especially the 2.10, but I also greatly prefer running gas. As far as the air frame goes, it's built to carry a heavy engine, like an Evolution 35. So those bigger displacement engines are right at home in this bird. A DA-50 was my first choice, but I didn't like the stand-off distance for the DA. Then I considered all other 50's as possible alternatives. Remembering how much I liked BME 50's in my other planes, I took a close look at it. It's a perfect match, even the H 9 engine mount works. I have a DA-50 in my RV-4 and it pylons with the best of them and lands like a trainer. So my thinking is, a Sundowner built for speed will do even better than my RV-4.

I like Saito engines very much and they have their place. But glow powered four strokes really take a beating at consistant and continual higher RPM. Plus everyone that owns one, knows they are glow fuel burning hogs. I have no doubt that the Sundowner flies well with a Saito 1.80. I would be surprized if it didn't. But the bushinged rod and bushinged cam will be history before too long at these higher speeds. Not to mention the mess that glow fuel makes.

[rcplane]

Hay CRG
How fast are you going with the Saito and what Nitro % are you using?
There are 6 guys here with 180s in their Sundowners and 2 or 3 are burning 60% Nitro! We clocked one @ 135 (with a Bushnell radar gun) but it wasn't really getting all it had I don't think.
I have to try to keep up with these guys with my Evo 35!
I cant remember where I read it but there is a guy who says he is getting 145mph with a Moki 210?

A DA-50, WOW!

PS; Get your pictures, this is Mike B

[mfuess]

	Quote: Originally Posted by rcplane
	Hay CRG How fast are you going with the Saito and what Nitro % are you using? There are 6 guys here with 180s in their Sundowners and 2 or 3 are burning 60% Nitro! We clocked one @ 135 (with a Bushnell radar gun) but it wasn't really getting all it had I don't think. I have to try to keep up with these guys with my Evo 35! I cant remember where I read it but there is a guy who says he is getting 145mph with a Moki 210? A DA-50, WOW! PS; Get your pictures, this is Mike B

It wouldn't totally surprize me IF the Saito 1.80's did get 135 MPH. However, it's not an every day occurance. In order to attain 135 MPH, a Saito 1.80 would have to turn a 15x13 prop at 11,000 RPM. In order to make this happen, the 1.80 would have to yield 6.257 horsepower. It is possible!

There seems to be an air (drag) barrier for this aircraft right at 135 MPH for most engines. In order to over-come it, you really need a lot of horsepower. A Moki 2.10 can barely pull beyond 135 MPH using a larger diameter and bigger pitch prop.

The only truly accurate way to clock this aircraft is using an on-board GPS. I have an on-board flight recorder and I doubt its data almost as much as I question a ground stationed radar. BUT what the hell, all of this is for fun anyway!

GO get em' SAITO GUYS...

[mfuess]

Just so you guys will understand:
IF you plan on racing your Sundowner, speed alone won't do you any favors. Your aircraft (and you) must be capable of turning a very SHARP left, recovering your top speed in short order, AND keeping a TIGHT line all at the same time... Smaller engines will provide a competitive top speed, but they cannot and will not recover from super high G turns as good as a bigger engine spinning a bigger prop. It's just a fact of life. That's why there are rules regarding engine size for any particular class. With all things being EQUAL, it's completely up to the pilot to fly a good line, and stay ahead of the pack (or catch up).

All the horespower in the world will NOT make up for crappy pylon skills. Don't take my work for it, put up some Pylon Poles and give it a try... you'll quickly see what I'm talking about.

[CRG]

Hi Mike,

Last time out I'd say it was doing about 110-112mph, just a fraction faster than the EVO35 version. This is on 25% nitro and an APC15x12 prop. It does use a lot of fuel, 20ozs. is good for around a 10 minute flight and no more.

60% nitro is a little excessive. As mfuess says, it'll only take that for so long. And you need a lot more power to go a little faster. I flew competition old timer for a while running high nitro in four strokes and they would eat pushrods and other parts fairly regularly.

One thing the Sundowner likes is to be light. The Saito will keep up with the EVO, but will out turn it at will, almost three pounds less makes a huge difference in the corners.

Got the CD of your Parker pics, great job Mike.

Craig.

	Quote: Originally Posted by rcplane
	Hay CRG How fast are you going with the Saito and what Nitro % are you using? There are 6 guys here with 180s in their Sundowners and 2 or 3 are burning 60% Nitro! We clocked one @ 135 (with a Bushnell radar gun) but it wasn't really getting all it had I don't think. I have to try to keep up with these guys with my Evo 35! I cant remember where I read it but there is a guy who says he is getting 145mph with a Moki 210? A DA-50, WOW! PS; Get your pictures, this is Mike B

[Sparky69]

I echo CGR. My Sundowner won the race at Parker and it wasn't the fastest plane on the course see my prevoius posts. Race #3 is the most studyed Sundowner with about 25 flights with full fdr down loads. From my data I don't think a Moki is running 145 MPH but I am not done testing. Again see my previous post about speed on the course not flying in a dive for a mile maybe.... It also has to hold together in the turns, I'm not confident that at 145 it would stick together.
I disagree the GPS speed is more reliable than what I am doing. It would be nice to have that as well and if you want me to install the GPS unit send checks my way. Remember I am recording all the time and can clip out a 2.5 minute sample from my data to study as I am wizzing around a simulated race course not a one time snap shot from a radar gun.
Sparky

[mfuess]

Sparky69,

I am in total agreement with you and CRG. I put 2 flights on my BME 50 powered Sundowner yesterday and it was a little disappointing, even though I did the math prior to flying it. I had expected a little more in real flight. With everything being brand new I used a 16x12 prop to hold it back a little. Boy, did it ever! My best peak speed was a piddling 107.6 MPH as documented by my flight recorder and confirmed by my calculations. Each lap I pulled the Sundowner closer to the poles to see where my limit is on how sharp it will turn & retain most of its speed. About 170 ft. is as tight as it will do right now. I expected that under the current conditions. Today I will try a 16x14N. That "should" push the Sundowner to about 128 give or take a little. Once the airframe has proven to hold up, I'll move up another pitch or two and see where that takes it.

The only redeeming thing is, it will fly for 40 minutes on 20oz. of gas.

[Sparky69]

M Fuss,
I over looked the GPS tracker giving radius of turn. You should be able to dial that down some. I think when we did the math we predicted 100' turn Dia (50' radius). Are you talking Radius or dia turn?
Sparky

[rcplane]

Why the smaller prop on your motor CRG? Shouldn't a Saito 180 spin a larger prop like was used on the EVO 35's at Parker? Wasn't it a 16x15?
It seemed like the parker prop made my plane much faster than the 15x12 I thought we were going to race with. I wasn't sure it was going to pull it when I first heard about it's size but after a couple runs it really liked it. No heat problems or anything.

On the fuel, one of these guys burn's up Saito's like they are free using that high Nitro, seems silly to me but then I don't have a big pocket? They dead stick a lot also where I never do with my gas!

I want mine to be able to fly in USRA races so I am going to keep the EVO35 in it, besides it really doe's fly good.
I also agree Sparky 69, I am not sure it would hold up to 145 mph. I was sure I could see the wing bend in good tight turns with the EVO35.

I thought mine was right at 13.5 when I took it to Parker but when it was weighed at the race, it was 14lbs. (poor home scales). I do still have the large solid rod in the tail but had to leave it in for balance (even though I have my rx battery in the tail).
In an effort to get mine lighter before Parker I removed the one rod, then moved everything back, ign, fuel tank (and smaller tank) and a tiny 2 cell lipo for ign to get it to balance.
I was curious as to how guys had gotten their planes lighter, then I found out about the light weight radial motor mount in Parker for the Evo35, with it in place of that huge stock motor mount and the large rod removed I will be much lighter. It might even be too much and go under the 13.5 the USRA has set.
The guys here with Saitos are 11.4-5lbs without trying? Hard to compete with that.

Some club members are trying to get some racing going here in a couple different classes, Sundowner, Q-500 type and a few others. I am going to try (for the club) and get a waver for some of the distances as they are quite large and even though we have a big place we still fall short of some of the AMA's set distances.
We keep safety first but can't meet a couple of those distances and as I just learned about the waver it sounds as they are quite common. As long as your request is sensable.
They are leaving the motor size open on the Sundowners and I am not sure they will get approved that way, although top speed can't exceed 135mph.

Does it still sound like the USRA will keep the EVO 35 on the Sundowner for 2008?
Or change to the Moki 210?

I can't wait to hear what Mfuess ends up with for top speed!


Mike

[mfuess]

	Quote: Originally Posted by Sparky69
	M Fuss, I over looked the GPS tracker giving radius of turn. You should be able to dial that down some. I think when we did the math we predicted 100' turn Dia (50' radius). Are you talking Radius or dia turn? Sparky

It's a 150' Dia. or, 75' Rad. I can pull a tighter turn, but I noticed a fairly substancial speed loss. My speed recovery is good, but it could be better. The Sundowner is rock solid in tight turns. I read somewhere that it yaws a bit in a turn, however I didn't see it. I flew a couple more times yesterday trying to get it all dialed in. I'm still disappointed in the speed. I switched to a 16x14N APC and it tachs 9720. This should have yielded 128.6 MPH. Instead, I got 100.6 MPH. That's 7.2 MPH slower than before. Dammit... OK, this tells me that it needs more thrust on the topend to overcome the drag. So narrow props are OUT. I'm fairly sure I can pull a 16x16 with authority but I won't know until I SPEND more money on props.

I think I'll fly my Rearwin Speedster today...