kevinbell

My Feedback: (2)

I would like to know any ones opinion on engine choice for a Extra 300 30%. It's an IAD Model Design Extra 300 91" span 1490 in sq wing. I'm in the middle of building it and finding it a bit heavy for what I would like it to be capable of.... 3D.... I have a ZDZ 60 and think it's too heavy, bare engine is 1.95kg or 4.29lbs.

I calculate the plane when it's built dry will be 8.14kg or 17.9 lbs. I think I can lose about 300g or 10.5oz on carbon bits from the UK. (anyone know good places in the US for carbon bits?)
I don't think it's enough weight too loose. Canopy alone weighs .372g or 13.1oz.

I'm using the Extreme Flight Yak 87" span model as a bench mark. (1450 in sq 15lbs)

Do I run a ZDZ 60 6 hp on the extra 300 weighing 7.83kg or 17.24lbs or a DA 50 5 hp weighing 7.22kg or 15.9lbs??? Is the .630g or 22.2oz worth it's weight in power? I mean having the extra 1 hp on the heavier engine, is it worth having?? Would it fly as slow? Would the DA 50 be similar or enough for a 7.22kg or 15.9lbs aerobatic plane? I want a low wing loading..

I've only recently started to fly high powered light aerobatic planes. I would be disappointed if I couldn't prop hang on 50% to 65% power. I do like powerfull light planes now.
Am I being silly for over analysing or what?

Tired Old Man

My Feedback: (1)

The ZDZ 60 is not going to have the 2 additional pounds worth of benefit. Although the ZDZ 60 is a great engine, the lighter plane will fly better with the DA50 that the heavier plane will with the ZDZ 60. The DA 50 has an extremely strong track record for planes in the 15 to 18 pound range. A factor that may need to be considered (other than weight) is availability, service, and price. Your location may make the ZDZ a more attractive engine due to those factors. Your call.

rmh

Try this --the ZDZ 60 bare engine -vs bare engine DA50 is one lb difference.
now add the prop/ignition - the ZDZ swings more prop which is a couple of more ounces -
Now select an exhaust system which does no harm yet is quiet- a bit more weight again for the 60 -but both engines fully optomized - the ZDZ has more power - typically on non tuned setup -a large can muffler - expect mid 6000 rpm on Mejzlic 24x10. The real issue tho-- is the bulk of the model 1500 squares on 18 lbs is really pushing it for even fair 3D flying on the 50 -
15-16 lbs is really where you want to be for brisk 3D flying on any 50 - I crank my ZDZ50 at an honest 7200 static on 22x10 Mejzlic and 7750 on 22x8 Mejzlic and 7200 on 23x8 . This at 15+pounds is good 3D at 17lbs -it would be ho hum.
There are very few 50 size designs that really crank 3D on a 50 and these are 15 lb setups.
Your comments make me think you are after performance like a good foamy -quick strong power -in any position -
Some guys are happy with 18 lb 50 powered setups and they can do the tricks but no leftover power .
So -afte all that - decide now -before you finish up what you really want . If you truly can hold under 16 lbs with a piped DA50 - it should be OK but look at my power numbers . It takes this kind of revs on these type props to really get fast response 3D-on a 15-16 lb setup.
Do not rely on the carbon fibre to save enough weight -a few ounces at best - real savings are in basic design-typically an 8 lb finished airframe --come in at 16 lbs all up.
I just did a 5.8 lb airframe (260 Extra) 1135 sq in- and all up? 11.5 - which is 8 ozs over target
RATS! So now I have to go back and do a final re-do I may cut 4-5 ounces that is it.
Had I done the basic airframe -Iwould have easily cut the 8 ounces .- My older 1150 sq incher were 10.25 lbs and a 1280 sq inch with gasser 11 lbs .
I do have the EFYAK piped 50 at 15.5 -that to me is a max weight for really sharp performance.

Nogyro

My Feedback: (10)

Dick,

I'm getting real close to those same rpm numbers on my DA50 & Mejzlik 22x10. Can you tell me how the flight characteristics changed when you switched to the 23x8 Mej. on the same airframe? Mine are in the 28% WH's and both weigh right at 17lb. 10 oz. I was thinking about trying the 23x8 Mejzlik. Thanks,

rmh

The 23x8 is superior to the 22x10 -tho each turn same static rpm.
why? the 8 " pitch unloads faster .
For pure precision aerobatics tho -- the 10 is better
A strange prop is the 22x8 Bambula I also have flown and compared - it tachs 6600/ 6700 on the ground.
Yet in the air unloads to 7700.
It actually has a much wider loaded to unloaded varience than the Mejzlics.
It is not a good 3D prop but an excellent , quiet prop for sequence flying.
Your plane is both larger/ heavier so the choice would easily be the 8" pitch
Check with DA I think your engine should easily run upwards of 8000 in the air with no mechanical problems.
These things really don't make best power till they are running fast -

Nogyro

My Feedback: (10)

Thanks for the info. That is my problem though, I enjoy 3D, but also mixing it up with IMAC. Just flying the Sportsman now for the fun of it. Seems like all the contests are TOO far away to attend, but learning the sequences and self critique is fun and challenging. I may have to give the 23x8 Mejzlik a try on my Edge, it really does 3d better than the Extra.........

car147

Kevin.

I have the IAD Extra on the ZDZ60 and the performance for 3d or anything is fine... I also have the DA50 in a Ultimate which threw the Con rod/Crank within 1.5 gals....[>:] you pays your money , take your choice.

Personally go with the ZDZ, a bit slow to start on the first run of the day, but afterwards 2 lip once warm.. plus no issues with this engine. I for one wont buy another DA.. either their quality control failed big style, or they decided to test a new design on joe public!

And it prophangs just below half throttle................... no problem

Rcpilot

My Feedback: (78)

No substitute for cubic inches.

Go for the ZDZ 60. It'll outswing the DA--and not by just a few hundred RPM. It'll swing a bigger prop at the same RPM as a DA on a smaller prop.

Bigger displacement = bigger prop = more thrust = more

chipline12

My Feedback: (1)

I have the lanier 30% edge540T @ 19.2 lbs w/zdz60 and zinger 24x10 prop. It is unlimited but still a little sluggish. I have never been a fan of the zinger props. Does anyone know of a better prop from Menz or Mejzlik to give a little better performance?? This person was running 87 octane and a wierd brand of oil. Will the better grade of gas give better performance also?? Any help is greatly apperciated

rmh

If Ed has em - the 24x10 Skorepa --a wood clone of the Mejzlic for less than 1/2 the price -is a great runner.
try , ESComposites.
Guys who think the DA50 is equivilant to the ZDZ60 have apparantly not run the two side by side
both good engines but the 6/5=83% displacement advantage is readily apparant.
We ran zdz60's --- a lot--- at 6400 on MenzS 24x10 props- The 3W 50's were close but still a couple of hundred shy and weighed more .

DiscoWings

My Feedback: (76)

what about the evolution 58?
That is about the same weight as the zdz60 but makes even more power.

bpryor

My Feedback: (45)

I'll second that MVVS/Evolution 58. The ZDZ60 is a good engine, but it's an old design. ZDZ has updated their 50's and 80's with new design motors that put out more power than their predecessors. The MVVS is already of a more advanced design, similar to the new ZDZ's, so I would strongly recommend the MVVS over the ZDZ in this size.

rmh

well the chain saw types are even older designs and they run well
The ZDZ60 setups I have had crank MenzS 24x10 at 6400 on tuned can .
How much better is the new MVS58 - I bet it is very close .

bpryor

My Feedback: (45)

I'm surprised you think that Dick, knowing how good the new ZDZ designs are over the old ones. The MVVS 58 turns a Mezjlik 24X10 at 7000 with the MVVS 3204 can. As you know, with a tuned exhaust it would even be higher. I personally don't think the ZDZ60 and MVVS 58 are even in the same ballpark.

rmh

Yes they are good -better than the old open port sleeves -but on a pipe that 60 is still a very good runner.
On the Mejzlic 24 x10 the ZDZ60 on a similar exhaust -will run in upper 6000 range.
The new 58 is a good design no question about it . It should run harder .
I was only noting that the good exhaust setups help ANY engine -even the chainsaw refugees.

bpryor

My Feedback: (45)

We certainly agree on that, though for most people it's still too daunting a task to take on(at least that's the perception), even though the benefits are substantial. As I mentioned, I think that will continue to change as not only the pressure to reduce noise increases, more and more planes are coming out with tunnels already installed, which makes the decision to go with a can or pipe much easier.

rmh

My new H9 260 is presently undergoing it's third pipe setup (actually from pipe to muffled can) -this one should be it.
If I had stuck my ZDZ50 and full pipe in it it would have been too much total weight for what I wanted That setup in the 15.5 pound YAK is serious power .
So I opted for the ZDZ40 RE and JMB can - weightwise. in that size -you are not going to beat it - The next best would be the new MG cased 45 Evolution/MVVS on their can.