Update

DA sent the prop and their muffler overnight express. Was certainly no need for that but I do appreciate it. Ran about 1/2 gallon through it swapping mufflers and props, see results below.
I am pleased at how this engine has turned into a one flip starter. It runs very well everywhere. The BCM is a bit quieter but the DA sounds more "manly".
Todays results.

Pro-Zinger 22X10
BCM 5900 rpm
DA 6700 rpm

NX 21X10
BCM 6100 rpm
DA 6900 rpm

Mejzlik 22X10
BCM 6300 rpm
DA 7100 rpm

Time to quit playing around with this and mount the engine to the plane. Quite a difference huh? Choose your muffler/prop wisely. This engine will be mounted in a H9 80" cap that should weigh around 15 1/2 lbs.

Dave

Thanks Dave for the data. It appears that your engine picked up some rpm from the break-in. It also shows that the DA is equal to a healthy Brison 3.2 when it is not held back by the Bisson muffler.

daveham,
Thanks, it seems they have delivered . . .as advertised!

NOT A PAID ADVERTISMENT! and he's not my brother-in-law!

Thanks again for being our "Test bed" can't wait until you get that "One Flip-Fifty" in the air.

We are all living out our DA 50-R Dream through you . . .


BigRagu

BigRagu,

"Sweet Dreams"


Anyone remember who the guy is that offers standoffs on here?
The ones supplied are too long form my application.

Dave

hey guys

what about the zdz 50rv? its 5.7hp 7000 rpm rotary valve and 5 ounces more in weight than the da 50. which engine is better? the zdz is also $75 cheaper.

Engine stand offs
Here you go>http://www.aerografixs.com/
Guys name is Roger.Good luck with that DA 50, looks good!

Doug

Thanks stomper, thats the person I was thinking about.

Dave

DAVHAM,

Thank you for sharing your test data with us. It is quite interesting to see the major differance in RPM just switching from one can exhaust to another. Looks like Bison really missed the boat. Since the Bison pitts style mufflers are on back order I called and talked to DA about possibly switching to their exhaust so as not to loose all the RPM. They said they were switching to Slimline pitts exhausts and those on back order will be filled with a Slimline. Although they haven't tried one yet Slimline is saying the RPM numbers will be equivelent to DA's. I'm keeping my fingers crossed for a pitts that will let this engine turn 7000 + with a 22 X 10 after break in.

davham can you take some pics. side by side of the two mufflers,are they really that different?

Say Windbuster:
Doing the math on the manufacturer's websites shows that the ZDZ-50 and DA-50 should weigh within an ounce of each other. It would be interesting to see some open exhaust numbers using the same prop on both engines, and also using mufflers of comparable design and outlet diameter. RCS quotes 7,000 rpm with a 22x10 Menz-S for the ZDZ, but they don't list the muffler used. They only list the Bisson Pitts and Side Mount mufflers for sale, so it's probably (?) one of those.

alright folks.....who has experience with the da and zdz 50 engines....which one is better, durable and most or all long lasting?

Windbuster:
The first DA-50 was shipped last week, ZDZ-50 maybe 2 months ago. These things are too new to have any long term data on reliability or problems. You'll be lucky to get bench performance test results. Maybe the guys in Canada can install these engines in their snowblower and report back?

davham or anybody:
Have you considered the fact that the ends of the exhaust pipes on the Bisson mufflers have rolled ends causing a restriction of sorts. One of our club members is an engineer, and calculated the amount of restriction before and after cutting off the rolled ends. In terms of square inches of area, cutting off the ends almost doubled the area. I couldn't believe the difference he calculated. The Pitts type muffler was for a 3W-35 engine. He had a substantial increase in rpms. Did davham cut off the ends of the exhaust pipes on his Bisson muffler?

The Slimline Pitts muffler on my G26 cuts 500 rpm from the same engine with no muffler at all...A standard Abell muffler loses only 200 rpm, but is louder..There's a fine line between size and power..Maybe Slimline will design a new muffler that would be tuned, making the engine even better..Still waiting for my very own DA50..Maybe next week....

rcign what you doin buyin one of them there store bought engines fer.cant you makem bigger better and lighter yerself.

LOL

Darin

When I ordered my DA50 (and yes I have had it for about 2 weeks), Dave @ DA said that with the BCM, you would loose a few hundred rpm. But he said if you cut about 1/4 of an inch off the exhaust stacks you would gain that rpm back, and as davham put it, makes it sound more "manley". I still have yet to receive my muffler. I guess BCM was/is having a problem supplying the demand....

OH OH.. Busted!! I got mine for less $$ because it came without ignition..I know someone who makes it Couldn't make anything lighter anyway...

Where did you get your DA from without an ignition? I just bought my World Model Extra today and will be ordering a DA 50 this week. Does anybody know how long the wait is to get one..

Where'd he buy it???
Two hints.. it wasn't Aircraft International or Cactus Aviation.


If you call up DA, I'm sure they'll sell you as much of or as little of a DA-50 as you like. Ya just has to pay yer money.

Exactly..Buying a DA 50 with ignition would be like buying a C&H ignition for myself, or C&H buying an ignition from me....Or Reichmuth, or Pro Spark, or Silent Spark,etc.....
I do buy coils from CH......

Anyone have any DB readings on this engine? What muffler and prop?

Thanks

Ron

After reading a few of the above post I went out and looked at the Bisson, and sure enough it's rolled in. I will cut 1/4" off each end and test it again with the Mejzlik prop.
I would rather use the Bisson for cosmetic reasons only. The DA will require a large portion of the cowl side to be removed.

Dave

To davham:
If you have a micrometer, measure the outlet hole on the muffler pipes before and after the cutting. We calculate the area before and after produces an increase of almost 50%. Although it doesn't look like it at first glance, the rolled ends really restrict.
Cajuncharley

Any input from Desert Aircraft regarding this issue?
I have one DA-50, not boken in yet and would like to know the end of this history.

I had talk several times by phone with Dave Johnson at Desert Aircraft, and it seems to me he is not the kidn of person that sales pineapples as apples.

So is recomended to get this to an end instead of live it floating...

Thanks,

Miguel

Have any of you guys considered the BME 50? It makes 7200 with a Mejzlik 22x10. I have NEVER had a deadstick. I am using the J&A pitts muffler and its about 99db @3 meters.

The DA's are beautiful though.......

Bob