I have a 2 gallon new DA fiddy. I have a 18.5 lb plane, and man, it struggles to hover anything less than 7/8 stick. I have a 23x8 NX prop. Its tuned very solid. Leaned until no transition on low, then richened enough to transition. Top end just leaned enough to NOT 4 cycle. Oil is still on lanboy break in per ratio and instructions. I have a JTec pitts muffler on it. Is this normal? Some folks say "oh no, it hovers my 2.3 Comp arf at 19 lbs at 1/2 throttle". I have been told by a factory pilot for CA and DA that it "will not hover well, but it will need running starts at uplines , yet barely hover". I do not have a CA 2.3, just an example. I have a hand built extra 31%. Thanks.

So what is a DA 50 with 23x8 NX prop static? 20lbs?

I have a 17.0lb. Wild Hare Edge 540T and I have several gallons through my DA 50 /Mejzlik 23x8 and Slimline Pitts. It hovers at 3/4 throttle and pulls out, but not hard and fast. A DA is the best 50cc motor made in my opinion, but it will NOT jerk a 17+lb. plane out of a hover at all. I like the power I have, but to have the power I would like I still need to loose a pound. I'm too used to flying my foamies with a 2+:1 power to weight ratio.

Sounds like your engine is right on track, it is just not as strong as some guys say in real life. There are three at my field and all run identical to mine.

Norman Ross

I love the hell out of my DA 50 and am NOT complaining..... I just found it dissapointing that it would jerk the 18 lb.er out of a hover... But according to the gurus of 3D , their 20 lb Comp Arfs are Yanked verticle at 1/2 throttle..... I just want to know what to expect. I love my Da 50... bought another

Using the MVVS Power Calculator Chart and the following data:

Altitude Sea level
RPM 7,000
NX 23x8prop Approx. 32 lbs. thrust.

Karol

So, 32 lbs should rip my 19 lb plane to the moon....?

Depends.... what rpm are you getting on that prop and what elevation do you fly at ??

Karol

I am 1500 ASL.... And.... 23x8 NX prop........ 330 extra @ 18-19

I need the max. rpm numbers.

Karol

At your elevation of 1500 ft ASL, and an approx. 6,800 rpm on the NX 23x8 = 30 lbs. thrust.

These numbers suggest that your plane should perform quite well as your power to weight is very close to a 2:1 ratio which is considered as fairly good for 3D flying.

Karol

The MVVS & Thrust HP calculator significantly over estimates the real world thrust you will actually see on a plane. The DA 50 or BME or ZDZ or Brison 52 will not give you the blast out from hover performance you are looking for in a 19 lb plane. You can add a tuned pipe but then you will have close to a 20 lb plane. The kind of performance you are looking for with the DA-50 comes on a 15-16 lb plane. I have never seen a DA-50 on a comp 2.3. I have seen them with a ZDZ-80 and I still don't think it had 1/2 throttle hovers. Your best bet is to find ways to lighten the plane.

A 19 pound plane is about 20 pounds with fuel assuming a 16 oz tank. The thrust off a DA50 with a pitts muffler is about 26 pounds (max) from actual measurments that people have done with digital fish scales. So you have nothing near a 2:1, closer to 1.25:1. That's why it's sluggish to pull out of a hover. Get it down to 15 pounds and you're talking a whole different story.

Also you need to fully break in the DA 50, use a less restrictive muffler, and tune it properly to get all that power.

My experience with gas engines indicates that measuring the thrust is a good idea. A digital fish scale at Wal-Mart is $17 to $30. I purchased a scale recently and it was a good addition to my measuring instruments. The scale can also be used to measure the weight of the airplane. With a full load of fuel the weight of the airplane will almost always be heaver than you think and sometimes by several pounds.

It is impossible to tune without good non-emotional data.

Bill

It's My calculator, not MVVS's.
Thrust at 1.5 times the plane weight will hover, and accelerate slightly in vertical, but not rocket out. You need 2:1 to do that, so it seems to me that the calculated 30 lbs is pretty close to actual 3D flight observations. That 19 lbs plane would need closer to 38 lbs thrust to perform crisp 3D.
Also, thrust may be reduced if the cowl has a large frontal area. This thrust reduction is not yet incorperated in the calculator, which for now is based on a normal, Extra-like cowl. A Jak would show slightly lower thrust figures because of the large round cowl if the airflow through the cowl is not well regulated.

FWIW I have tested my DA50/KS1060 Mej 23-8 70 degrees 600 ASL, at 6800RPM is read 25.4 lbs on a very good fish scale (truth machine) made by rapala. I indeed had this engine on a comp-arf 2.3. I could not hover it all too good and I was just learning that trick, a competent 3D flyer at my field could hover and TR it with good vertical pull out. That plane/engine combo is a blast to fly and when the 2.3 yak come out I'lll have another.

Dart, you may or may not be happy with this engine on that plane. It all comes down to how you like to fly. My 2.3 weighted 19.3 lbs and it was a joy. I'm a big DA fan and they keep me in the air 24-7 365 JME!

JOe

I fly a DA50/Slimline pitts. I have about 7 gallons through the engine mounted on a Sig Sundancer. I estimate the weight of the plane at a 17.5 pounds. I found the NX 23x8 loaded up the engine too much. A NX 22x8 had the type of vertical I was looking for.

I just switched to a Mejzlik 23x8. It didn't turn up like the NX 22x8 but it had the vertical of the NX 22x8. What is really nice is that the Mejzlik is not as noisy as the NX 22x8.

The only bad thing about the Mejzlik 23x8 is it weighs 2 oz heavier than the NX 22x8. It was enough to change my balance point. I am now re-arranging batteries in the plane.

Pe,

Sorry for that brain fart on my part regarding my error on the ownership of the 'Calculator'. No offence mean and hopefully none taken. Cheers

Karol