Da-85 - Actual Field Results

[flyin woodbutcher]

	Quote: Originally Posted by KrisW
	Hmmmmmm. . just wondering. . anyone run the 27A on the DA-100? It would be kind of embarassing of the 85 was as strong, if not stronger than, the 100.

DA owners are never embarassed.

FWB aka Fuzball

[EXTREME FLIGHT]

Tom those results are amazing! You've got me excited.

[xtraflyr]

Yeah me too Chris.. Got that 85 in the Yak yet? HAHAHAHA!!!

[Rolling Thunder]

	Quote: Originally Posted by wildhare
	I ran some side by side tests of DA-100 vs. DA-85. Both had canister setups and 27-10 bunny (xoar) props. The 85 came out 80 rpm below the 100. Since them I have changed the canister muffler on the 85 which picked up about 140 rpm. So as it stands the 85 is slightly ahead of the 100. The being said, I have done nothing to try to peak up the 100. It runs well so I know the needles are very close, but I might be able to get a little more out of it by fooling around with it. I honestly don't care, it has plenty of power for my purposes. I have not experimented with mufflers, just put on headers and mufflers that fit well in the plane. There may be a little more there, but it runs quite well so I don't thinkI will find another 300 or 400 rpm. I did change both engines to Mejzlik 27-10TH, the 85 picked up 200 rpm with that change at the expense of a lot of noise, presumably the 100 benefited similarly. In summary there isn't enough difference between the two engines to make your choice on power. I like the 85 because with the canister setup on both engines the 85 will be 2 pounds lighter, aircraft performance will be better with the lighter setup. TF

How many rpms are these engines turning. I have a hard time believing both engines on pipes are running that close.

My DA 100 on homemade greves style pipe is running 6600 rpms with a 28-10 mej.
My DA 85 with a MTW 110k is turning a Menz 26-10 6250.

the 100 is in a 27.5 lb A/W 260 and it is the most powerful plane I have ever flown.
the 85 is in a 23.7 lb radiocraft extra 330 and it has just enough power.

[Dgeorge]

My Da 85 on a pitts with less than a gallon of fuel is turning 6450 on a Xoar 26 x 10

[wildhare]

	Quote: Originally Posted by Rolling Thunder
	How many rpms are these engines turning. I have a hard time believing both engines on pipes are running that close.

On a 27-10 bunny/xoar tyhe 85 turned 5900 and the 100 turned 5980. These props are a big load.

It is possible that my rpm is wrong, my tach is not calibrated to any other, but I measured the engines 5 minutes apart at the same field on the same day with the same fuel from the same gas can. The relative RPM is accurate.

As I said, I made no attempt to optimize either engine setup, I just got them to the point where they feel like they are running well and measured them. There may be more there.

As for 6600 rpm on a Mejzlik 28-10, my 85 is turning a Mejzlik 27-10th, the thinner blade version, at 6240 with the K&S 95 can. The 100 has not been rechecked with the Mejzlik prop but its rpm sounds like it's in the same range.

Obviously there is a discrepancy between our test results.

TF

[sprice50]

	Quote: Originally Posted by wildhare
	In summary there isn't enough difference between the two engines to make your choice on power. I like the 85 because with the canister setup on both engines the 85 will be 2 pounds lighter, aircraft performance will be better with the lighter setup. TF

When you account for the additional header and cannister it would be more than 2 lbs lighter, guessing around 2.5lbs lighter. In a 25lb 35% bird this is 10% which is huge in performance!

[KrisW]

	Quote: Originally Posted by flyin woodbutcher
	DA owners are never embarassed. FWB aka Fuzball

ohhhhh .. . I dunno bout that now. . . .

I'm very glad to see reputable people like Tom Fawcett getting us some accurate and comparative real-world numbers on the DA's, and I'm presuming the rpm figures are after the engines are fully warmed up (which is really the only way to do it properly). Too often we see people get a bit (being very nice here) "enthusiastic" when quoting tach numbers.

I talked to Bill at DA last night (checking pricing and dimensions. . hint. . nudge. . wink . .. ). He told me over 600 of the 85's have already left the door. You just gotta wonder how much sleep the competition is losing over that.

[wildhare]

	Quote: Originally Posted by KrisW
	I'm very glad to see reputable people like Tom Fawcett getting us some accurate and comparative real-world numbers on the DA's, and I'm presuming the rpm figures are after the engines are fully warmed up (which is really the only way to do it properly). Too often we see people get a bit (being very nice here) "enthusiastic" when quoting tach numbers.

Gee, I always wanted to be reputable. I'd rather be young again, but I'll take reputable.

The engines were up to operating temperature when I tested them but it was not following a flight. They were run until it looked like any early peaks had subsided, but they would probably be a little warmer after a flight.

Regarding people being enthusiatic on tach numbers; Ya think?

TF

[Yakov]

	Quote: Originally Posted by EXTREME FLIGHT
	I am getting ready to install a DA-85 in one of our new 110" Yaks. I will be using the Grieves pipe and will post my results with this set-up. Hope to get started next week.

Chris,

When can we expect to see something on your site concerning the 110" Yaks?

Even a sneek peak at colour schemes would be a nice early Christmas Gift to your Devotees!

[Rolling Thunder]

	Quote: Originally Posted by wildhare
	Gee, I always wanted to be reputable. I'd rather be young again, but I'll take reputable. The engines were up to operating temperature when I tested them but it was not following a flight. They were run until it looked like any early peaks had subsided, but they would probably be a little warmer after a flight. Regarding people being enthusiatic on tach numbers; Ya think? TF

I agree, tach numbers can seem a little bloated. But even a wacky tach will work to compare 2 motors to each other.

I saw someone claim 6600 rpms out of the 85 with a 28-10 prop, I have to call shinanigans on that one.

[krayzc]

I have the 85 and all I see over the net is stuff like it has to vibrate more than a twin, it cannot be all that powerful, and on an on. I have never had a DA engine and I use to watch all the DA owners sing like there was nothing better than a DA. Well let me tell you I am singing on that bandwagon big time I am looking to audtion for the lead role lol lol lol lol yeah I LOVE my 85. as far as I am concerned I can let the 3 other gas engines go in my hanger (not going to but def a thought).......

other things things to get hot over

flights on a 5200 pack
holding power of my servo
oil mixture that I am using
weiight of my plane compared to you alls
how well the plane tracks

did i miss any (heck yeah)!!!!!
Gerald

[wildhare]

	Quote: Originally Posted by Rolling Thunder
	I agree, tach numbers can seem a little bloated. But even a wacky tach will work to compare 2 motors to each other. I saw someone claim 6600 rpms out of the 85 with a 28-10 prop, I have to call shinanigans on that one.

Here's what I don't get about people. Why would someone want to lie about this? I mean, it's not like they are bragging, they didn't design the engine ot have anything to do with the performance except to buy it. What's the point of posting exaggerated numbers?

6600 on a 28-10, wouldn't someone stop and say "I wonder if this can be correct".

TF

[KrisW]

	Quote: Originally Posted by Rolling Thunder
	I agree, tach numbers can seem a little bloated. But even a wacky tach will work to compare 2 motors to each other. I saw someone claim 6600 rpms out of the 85 with a 28-10 prop, I have to call shinanigans on that one.

Well. . ya know. . it SAID 28" on the numbers on the blade. But friction from a large number of flights may have worn the blade a little thinner and shorter than it originally started out at. . . . . . Then there's the mislabelling that sometimes happens. I once had a Mejzlik "28-12" that was actually a 28-10. Funny thing was, though, that it would turn 100 rpm faster than any other 28-10 I've ever owned, which also shows that even CF molded props coming from the same mold set can be inconsistent. You get a big enough set of tolerances working in the proper direction, all at the same time, and you just might see some really good numbers that don't reflect the norm for a particular engines power output.

Btw, the difference between 6600 rpm and 6000 rpm, with the same 28" prop, is about 1 hP of output.

[KrisW]

	Quote: Originally Posted by krayzc
	I have the 85 and all I see over the net is stuff like it has to vibrate more than a twin, it cannot be all that powerful, and on an on. I have never had a DA engine and I use to watch all the DA owners sing like there was nothing better than a DA. Well let me tell you I am singing on that bandwagon big time I am looking to audtion for the lead role lol lol lol lol yeah I LOVE my 85. as far as I am concerned I can let the 3 other gas engines go in my hanger (not going to but def a thought)....... other things things to get hot over flights on a 5200 pack holding power of my servo oil mixture that I am using weiight of my plane compared to you alls how well the plane tracks did i miss any (heck yeah)!!!!! Gerald

Here's what really matters:

The plane flies GREAT
The engine is consistent and makes more power than you will ever really need.
The servos do not blow back
You get tired of flying before the battery pack runs down
The plane doesn't do strange things like wag the tail, flutter, over-rotate snaps, or tip stall in a heartbeat, or blow apart in the air.
The covering stays ON
Your buddies appreciate your flying. . no matter whose plane it is
and the most IMPORTANT things:

You bring it home in one piece. .every time you go out flying
You bring YOURSELF home in one piece, every time you go out flying

Beyond that, there's really no other reason to be in this hobby.

BTW. . I use my tach so seldom that it has cobwebs holding it in it's box.

Personaly I'm glad DA has the 85 out now. Just one more nail in the coffin of certain off-shore imports, IMO.