flat spin

What prop?

twister

My Feedback: (12)

22x8 menz recommended by DA

flat spin

That sounds very low. Although run in now i get that on a 23X8 Mejzlik which i believe are harder to turn.

Could be that it is too rich but to drop that much RPM it would sound terrible if run at all. You may also not have the right lenght on the can.

I would say run it see what the engine is doing and if you can lean it out a little then go from there.

I am sure someone will have some other advise but i hope that is helpful.

Thinking about it i had a customer here who was getting very little power from the engine like very little and he phoned DA they asked him if he had is ignition in the right way. It wasn't and it sorted the problem immediately bit like is say he was well donw on power like take off was a strugle.

Good luck

twister

My Feedback: (12)

well the canister was the recommended setup 75cc header and all, what rpm should i be getting?

flat spin

I am sure there were posts earlier in the thread of people running 22X10 which seems to be the standard break in prop and they were getting around 7200-7400 if i remember correctly. Please don't quote me on this but if i am getting 6800 now on a prop 1" bigger that would sound about right.

Josey Wales

My Feedback: (61)

I broke mine in on a MSC 22-8 at about 6900 rpms..also tried a Menz 22-8 and got 7200 rpms with a Slimline pitts

Mike Parsons

We had a fun-fly yesterday and boy was it windy. 20 mph variable. Only had a chance to get one flight in with the Yak. Here is a short video of the flight. Nothing special, but this power system really delivers. All flying was done at 1/2 throttle and 3/4 uplines.

http://epowerflight.com/Media/50ccyak.wmv

bodywerks

My Feedback: (4)

What altitude are you at, and did you cut the header length down at all???
I ask the altitude, because I get 7000 out of a BME22X8 here at 6500ASL, while most would get 7300 at sea level. With the msc, I was lucky to get 6800.
As for the header length, as I have mentioned before, I origionally installed the Hyde cannister in my Yak and had to cut 2" off the header for it to fit right and started with a 23X8...I got 6200 rpm. Went to a 22X10...6200 rpm. Went to a 22X8...6200rpm. Took the cannister off and bolted on a stock muffler...6800, immediately, with the MSC 22X8. I am now running the BME and get around 7000.
I contacted CHP and he said that the header length most definitely ruined the performance of the cannister, and that is was designed around a full length header. I believe this is about the same for all cannisters.

Maudib

My Feedback: (51)

Very nice Mike,

What's the 4000 Watt power system? Esc? I see the TP logo sp I assume you used the 10s3p or 10s4p packs?

What was you're all up weight?

KatManDEW

My Feedback: (6)

Specs:
87" Yak 54
Electric- 14 lbs 12 oz/ Gas- 15lbs. 8 oz
Power- 2 Cyclon 160 Outrunners ganged to a single shaft (Atlantahobby.com)
Pro: 22X12 APC E
ESC- 2- Jeti 77 Opto's
UBEC- 6V redundant UBEC system
Batteries- 2 Thunderpower 8s2p 4ah Pro-lite bricks (one per motor)

Last I heard he switched to 8s3p packs.

Maudib

My Feedback: (51)

Oh gotcha... this is the one that was at SEFF too... gotcha... I didn't know Mike changed his RCU handle from Altantaeflyer...

NE0

My Feedback: (9)

Gas - 15lbs. 8oz???? Where did that number come from? Just as with the electrics, the gas weight varies depending on setup. Mine is only 15lbs 4oz, as are most with stock setup. Some are 15 even. The only ones at 15-8 are the ones using the aftermarket header/pipe combo, but those get quite a bit more thrust. I've seen electrics come in at the same weight as gas, so it's all relative to your setup. Just as not all gas Yaks are 15 even, not all electrics are 14-12.

Manufacturer specs are 14.5 to 17 pounds, which is a wide range to cover "all" setups. (Gas, electric, stock, header, smoke, etc).

Tom

basmntdweller

My Feedback: (9)

Neo,
I think he was generalizing the gas weight and giving the weight of his electric power version. I wish mine was only 15,8. Mine came out to 16lb 7oz. The only thing I did that added weight was I'm using a pair of 1650nimh packs for the rx, a 2000nimh for the ignition and a Slimline smoke muffler but no smoke system. Everything else was stock.
Matt

NE0

My Feedback: (9)

Yes Matt, but those "only" things you did add up to almost exactly the amount of weight that you are "over" 15,8.

Replace the Slimline with a stock DA muffler... save 7-8 oz. Kill the redundant batteries and switches... save another 6oz (approx). That gets you very close to 15,8. Use a CF spinner, save another 2-4 oz. Now you're getting closer to 15,4 like mine. It's all in the choices you make during setup. I'm not saying you made any wrong choices... just that they explain the extra weight your Yak has.

As for comparing the "generalized" gas weight of 15,8... It doesn't mean anything to compare that to an electric setup that has been "optimized" for optimum wingloading. For example, the electric plane listed above has NO spinner. Your saving a quarter pound there alone. You just have to make sure you are comparing apples to apples when comparing gas to electric weights.

Two planes set up exactly the same "EXCEPT" for powerplants can be compared... not an "average" gas compared to an electric at the lightest possible weight. Electric Yaks can come in at over 15 pounds too if not optimized for minimum weight.

Tom

Maudib

My Feedback: (51)

Sorry to seemingly start this thread going off again...

I was aware of Atlantaaeflyer's Yak, it's setup and weight and the one I put together for Chris per his specs, and I was curious as to what this new "Mike" did with his.

I'm not looking to compare electric to gas at all, though now that the weight issue WAS brought up, the one I built weighed 15.25 lbs without wheel pants but WITH a CF spinner... Mike's, if he does go to 3s pack will add about 1.5 lbs in doing so. Add a spinner to pretty it up and it's weight might be closer to 16 lbs...

But in reality, weight is NOT an issue with this plane... Though I LOVE mine, it is REALLY light in the air get's blown around a bit sometimes... it can easily take up to 17 lbs... so maybe you smoke guys aren't that out of whack afterall...

Cost isn't an issue either, it's an "eye of the beholder thing"

But being properly powered IS an issue and that's why I was curious as to what this potentially new e-conversion was using.

Chris said Mike's was approaching DA-50 power and that with an extra cell would have been ballistic.

I was under the impression from Chris that he wanted to go to 9s, but maybe that would increase the amp draw beyond the capacity of 2s 4000's.

Seems if Mike just added a parallel cell (going to 3p), he would add 20+ oz in battery weight, but not gain any power staying at the same voltage?

rmh

All canisters are not the same - not even close to the same
HUGE differences
Some have the header extended close to a baffle -or end of the can - these use a reflected wave -that must be synced with rpm.
Others used a huge volume and the header ends far before the end -or a baffle.
These produce mild back pressure and are not influenced much by rpm. Still, there are more differences
EXAMPLE:
The JMB 80x300 can is shaped almost exactly like the 95/110 300 can -but on my 80's reduces 150 200rpm .
Why ? smaller diameter header (inlet) pipe
from 6300 to 6450 -is a noticable difference if all other things (prop/fuel direct heat comparison.)
Switching to a tuned canister (overall much longer ) the rpm jumps another 100-200.
Going to a full length tuned pipe--- set for non peaky . smooth operation - rpm again goes up a few hundred more .
Exhaust setups make more difference than any engine mod.
Good "bolt on" setups are hard to find --I just spent the morning, redoing interior of a new H9 EDGE - to allow a JMB 95/105/ can to fit inside -for my 80
I think it is well worth the effort as I can swap thru a wide variety of prop with no tuning issues and performance is much better and far quieter than the in cowl devices.
The YAK-- I used the JMB pipe AUW 15.25 lbs -
23x8 - 7200 seems best overall prop --still lots of prop noise if allowed to gather any speed.
Tho I have not tried this pipe on the DA 50 -it should work similiarly.

bodywerks

My Feedback: (4)

Dick, who was your reply in response to?

rmh

-Looks like it was to a comment about all canisters being sensitive to header length-
I just looked - it was your comment about info you had received from Chris.
The oft published "how do tuned pipes work " etc., cause plenty of confusion for those wanted improved - but not critical length exhaust systems.
The types of exhaust systems for two strokers go back a hundred years -
And just going back 50 years still presents lots of varied info .
What is /is not a tuned device is quite varied .
I have made very effective tuned devices from a spray paint can and a length of ss tubing - no convergent/divergent cones etc., req'd.

Mike Parsons

Whoa.. at least the thread is moving again .

Neo,
When I completed mine I looked at this thread to see what the weight of one with a DA-50 and what I saw was 15 1/2 pounds. I looked at a couple and saw the same thing as an Average setup. So that is what I went with at list. I understand you point, but it is just a general comparison, not gospel.

Maudib,
Yep, my screen name changed when I became a moderator. Sorry for the confusion. The only change I have made is adding stack of Parallel, so now I am running 8S3P's instead of the 2P's. I picked up 19 oz with the extra P, but I dropped 9 oz of lead out of the nose, so it brought me right about 15 1/2.
It has lowered the resisitance and allows a little more juice to the prop. My amps went up to 70 at full and watts are now at 4200 watts. I would eventually like to go to a 9S, but will have to upgrade to the Jeti 90's in place of the 77's. The new 3P's can handle 100 amp bursts, but not the speed controllers. I am satisfied with performance it gives me now and will still be experimenting a bit.


Cheers,
Mike

bodywerks

My Feedback: (4)

Dick, I find it VERY hard to believe that one Chip Hyde cannister would be different than another Chip Hyde cannister. With that said, Maudib's report of a 200 RPM increase over the stock DA and my reported 500RPM decrease would have to be something different...the only real difference was the length of the header on his test bed verses the 2 1/2 inch shorter header on my Yak-mounted engine.
If I remember correctly, Maudib reported RPM losses once he actually mounted and ran the engine on the plane, so header length, IMO, is the obvious problem here. I know the guy that is having RPM issues DOES NOT have a Hyde silencer, but a silencer, nonetheless. So I threw this info out there as food for thought.
Also, it wasn't Chris that I talked to, to clarify, it was Chip Hyde.

jpa2002

My Feedback: (115)

Guys, I have posted my plane in the classifieds section, so if anyone is interested, I have reduced it to $2500. That is a steal! I just need to turn some stuff into cash, so I am reducing the price to the bare minimum.

Thanks, and if you know anyone looking for one, please pass this along.

http://www.rcuniverse.com/market/item.cfm?itemID=104819

Jon

rmh

Mis interpretation - All CH cans are likely the same - But how they are hooked up (header setups) and the props used are often, NOT the same.
I was trying to explain that various brand cannisters act differently
Ditto for Magic cans /Magic Mufflers/tuned pipes etc..
That is why I noted that the very similar JMB's, are different - because the internal tube diameters are different.
Also never consider any muffler /device, as improving power -unless you have solid open stack readings .
most of these devices simply reduce losses - not add power.
Some mufflers can chop 500 rpm from open stack power -and that is a huge loss.

bodywerks

My Feedback: (4)

True. I was unable to reduce very much "loss" with my Hyde pipe. I am sure I woul reduce "loss" if I went to a full length header with it, but I am happy with my stock muffler for now, as well as the 15lb. dry weight...I am in no hurry to go back to the cannister.
BTW, who here are on the wait list for his 100cc Yak? I am, and can't wait, although the plane is all I will be able to afford for a while...

NE0

My Feedback: (9)

Understood. I wasn't trying to cause a debate, just trying to clarify. The question was about the specs of Mike's "specific" setup, which KatMan did a very good job of. I just didn't understand why a "general" spec for a gas plane was stated in the same line?

One could easily interpret that as a comparison stating that an electric Yak is 12oz lighter than a gas Yak, which isn't a fair statement. Just trying to clarify that you have to compare apples to apples. Otherwise there is no value in even adding that spec for a gas plane. Nobody was asking what the average gas spec was... just what Mike's specific e-setup was. Just didn't understand where it was coming from?

On another note... just got back from puttin in flights 4 and 5 on my Yak. Would have put in flight #6, but the servo gremlins showed their ugly heads. [:'(] Took off and did a couple rolls, snaps, etc and then went into a level circuit. The elevator seemed way out of trim... ballooning very bad. I brought it in and found that my left elevator was deflected about 5 or so degrees from the right at nuetral! [X(]

It operated fine, but the nuetral point changed. Mechanically, everything seems sound. I need to did deep to make sure that is in fact what has happened. I spoke to two other guys at the field and they both have had the same problem with their HS5495 servos. One guy had an aileron do this, he called it "phase one" of the incident. He repositioned the arm on the servo and flew it again. After landing, he was taxiing and the same servo just slammed into full down and locked their permanently (luckily on the ground)... "phase two."

Another guy had one in his new Yak, settin up at home. Phone rang, he set the radio down, answered the phone, came back and the elevator was locked in full down with smoke pouring out of the plane. It melted the servo case, burning the stab. Then he also found that it melted his 6v regulator, scorching the balsa pipe tunnel. Had he been gone longer, may have caught the plane on fire.

Not flaming or trying to cause a panic, but be warned... keep your eyes on those 5495 servos. Every servo in my Yak and Vision are 5495's except rudder, so I hope I'm not in for more trouble. Fortunately it didn't cause a crash... "this time." [sm=idea.gif]

Tom

Mike Parsons

Tom,
The post that Kat made was copied from my RCgroups thread that was specific to this conversion. That is why the spec's were in there...as the question was asked many times from RCG members. I would be happy to amend it to your weight . It is just a generalization as to the difference in the two power systems and what the average weight of each was. Hope that clears it up .

-Mike