DocYates

My Feedback: (102)

Thanks Ron, more good information.
What kind of flight times do you think you could expect with the setup you recomended? Enough to fly a scale routine in competition?

Ron101

My Feedback: (22)

I think you could see 5:00 to 6:00 with throttle management.. maybe even more Twins are more efficent

cgrcjet

Ron,
What battery config. are you using with the stumax and what kind of output are you getting with it? I was curious to compare it with the turbax 9s , 10s setup that John has been using.

Doc,
You can try it, but i think the twin dynamax setup is a little overkill for the A10, although i like the scale realism it would add to the plane. I would like to set mine up with the stumax fans. You can get into some weight savings especially with a twin. Tam also has a fan combo coming out that is smaller and much lighter with good output. John has been waiting on the motors for this set up and i think Tam will be setting up his A10 with these. The A10 still glides and flies great with the turbax but i am just wondering how much better it could be with a lighter set up. I am just thinking lighter is better. Do you know the average weight difference between the dynamax and turbax?

Take for instance the Mibo A10 with a 10ft wingspan. Its not even twice the size of this A10 at a 6ft wingspan but it sometimes comes in up to 3 times the weight (70lbs). I am not sure how all these ratios work but even though the designs are not identical, the large wing area makes it more forgiving. I guess what i am trying to say, is that you should not have a problem with the dynamax but i would also look at the weight savings you could have.

thanks
chris

cgrcjet

I am just going to go through sics picture from the first page so you guys have a better idea of the parts in that pic.

-Top rows servo covers/mounts. I think you know where all these go.
-Next two rows flap hinges
-next row down from left to right
2 aileron horns
2 elevator horns
4 flap horns
2 rudder horns (I only see one here sic. I hope you have 2 of these)
6 servo straps
-last row servo retainers

Here is a bad picture of the servo mounted to the servo cover. I will try and take some better pictures today of this setup and the control horns.

Ron101

My Feedback: (22)

Chris I'm running 11s 30c 5000 mah in my Spark(2-4s+1-3s)... I'm getting 3600 watts with that...and the thrust is crazy. Stu's isn't the fastest fan but has really good thrust for vertical. With that said I'm still getting 170 mph at full throttle. Others are running it on 12s 30 and getting 4500+ watts
I know 9s will get you around 2700 watts....I'd guess 10s 30c will put you around 3200 watts... but this fan is lighter than the turbax

Stu Fans is about 1.8 pounds
pretty sure the turbax is around 2.2 pounds and the dyn-e-max scropion up around 2.5 maybe a bit more

Tams is the lightest I think it's 1.5 or a tad less.... so with Stu's fan or Tams your going to save close to 2 pounds of weight
Stu's sound just amazing! for a scale plane it's very hard to beat that sound, like a quite turbine... I'm a huge fan of Stu's
Tams is a light weight power house but makes more niose... he is working on a new 7 blade stator and a soft mount that may reduce the sound..
Stu's or Tams would be a great setup

Sound is very important to me... if it is to you then you have to go with Stu's Fan

Ron

cgrcjet

Thanks for the info Ron. So you think we could get away with a twin 9s setup with the stumax and still have some decent output? That would in turn save us some weight.


thanks
chris

Ron101

My Feedback: (22)

What was are do you think will be your ready to fly weight.... and you have to factor the weight saved with the Stu Max or TJ-100
if I new that I can tell you have many watts you would need

you should shoot for 250+ watt per pound for good performance

My spark has 327 watts per pound

cgrcjet

Ron
I am thinking around 20lbs. That would put it at 5000. Im guessing 2500 per side?

chris

BaldEagel

I don't know what you are on, but I want some too. LOL

Mike

DocYates

My Feedback: (102)

Will there need to a thrust tube built into the nacelles, or can the nacells work the way they are made? I have held a Dynamax fan unit up to the nacell and the forward lip mold perfectly into the edge of the fan, but like some of you, I am concerned about the weight. This fan with the Skorpion motor seems robust (have not run it yet), but it also feels heavy. My guess is that it will weigh much more than the Wren 44, but again I am looking at about 80% more thrust.
I may have to look at Tams EDF unit and price it before going with these two.

cgrcjet

Hey Doc,
We used the nacelle inlet for the turbax and i am sure the dynamax would be the same. I have made a new mold with a smaller inlet for the smaller fans. The inlets for the 5" fans will need to be specified when ordering. I will eventually get around to making some inserts and exhaust for the different smaller popular fans.

Check in on those lighter fans.

thanks
chris

Ron101

My Feedback: (22)

I've been doing big edf's for a couple years now and smaller ones for 5 years...

I'd go for the lighter setup...it's going to fly better and have longer flight times and cost less

Tam also sells a low amp version of his fan which could be a smart setup... he use's smaller lighter motors and CC 85 hv's to save weight
with his new 7 stator design and soft mounts.. at these low amp levels it will sound pretty nice...it's at the high watts it really screams

This sounds crazy but talk to Tam I bet it would work very well...
Drop down to his 6s setup it's only $699. plug and play with fan, motor and ESC, it only weights 1.2 pounds (these two fans would weight less than one dyn-e-max and the dyn-e-max still needs a ESC and CC 110 are over 5oz)
So just in the fans you save 2 pounds over your tubax or dyn-e-max setup ..that puts it at 18 pounds...
now you only run 6s per fan..a total of 12s 5000 mah.. so by droping from 10s per fan to 6s per side you save another 2 pounds..
so you hit 16 pounds.... if the CG works out... but I bet it would
on a good 6s 35c 5000 mah pack Tams fan will make 2000 watts (so a total of 4000 watts)

Put's you right a 250 watts per pound ... spend only $1400 bucks in fans and only have to run 12s....

I think that could be a killer setup as much as I love Stu's fan .. I think I'd try this setup
Ron

DocYates

My Feedback: (102)

What kind of thrust can you expect using the 6S setup of Tam's, Ron? I wanna save weight, but at the same time I don't want to be to borderline on the thrust, just in case.
Did the original model use one of Tam's units, CGRC? What was the original set up on the protoype?
Again, with this lower diameter fan, how much changes would need to be made to the duct inlet, and the thrust tube for the nacelle?
Thanks

Ron101

My Feedback: (22)

I talked with Tam this morning and he seems really interested in this project...
He is leaving for E-Jets in Ohio later this week and is getting ready for that, but when he gets back he wants to work on one.

He said the two 6s setups would give about 15 pounds thrust at 230 mph efflux... very light it would fly like a glider

At 16 to 17 pounds it would fly great!

Here's a video of a HUGE 25 pound Comp ARF hawk he did with two fans... and there is losses in that ducting
with the A-10 you won't have ducting losses.

http://www.youtube.com/watch?v=4EOtq-E7HYw

http://www.youtube.com/watch?v=bLB9_BsbrPE

this is not the new 7 stator fan which will sound sweeter... but gives you the idea of what it can do

later
Ron

cgrcjet

Hey Doc
The proto did not use Tams fans, they were the turbax fans. I dont know if you watched the video of its maiden flight with the turbax setup but i believe they were running 11s setup. At the end of the video the batteries popped and it lost power. You can see in the video,when its coming opposite way of takeoff, it banks to the right before turning and coming back in for runway. It banked to the right when it lost power. It glided very nicely back around for a safe landing (except the nosegear stuck). After that it always flew on 9s setup and never had any problems with this setup. The plane feels like a tank with this setup but still flies great. I am thinking the dynamax setup will be a tad heavier like Ron was saying. Its like a never ending battle, bigger fan more thrust, more weight. Anything will fly with enough power but dropping the ratios down seems better to me.

As for the ducting, i will be making some inserts for Tams fan and the stumax fan for now on the inlet side. I will also need to figure out the exhaust side which will be a little more tricky. We will need to figure out the best diameter for the output on these fans. John rolled up some styrene and used it as the exhaused ducting on the turbax. I think he just went straight back with it, with no taper. The older inlet fits the turbax perfectly.

Yes, Tam was getting some fans set up for the A10. I called him today also, to see about some other things for the A10 but he was not in. I dont think he has picked his A10 up yet. I think he wanted it flying for E-jets. Busy guy.

chris

Ron101

My Feedback: (22)

For the thrust tube you just want to use light 5mil clear mylar sheets
you need to ask what ever fan maker you run what is the best exit size to run... I know Stu's is 85 to 90mm
not sure on Tams...

you can just roll the size you need .. tape it up with clear packing tape or duct tape... ( I like bledrem tape)
if it hangs out the cones at all you can paint it to match.. very light and easy

BVM uses the same thing for all his stuff...cheap mylar

DocYates

My Feedback: (102)

Thanks for the updates. I finally opened up the boxes with the fan setups which I got from my friend who had decided not to use these and got out the paperwork. I misspoke, they are not Dynamax fans, but Ramtec (although I think they are essentially the same size). They are a little tight in the nacelles, and will require a little trimming of the hardwood mount in the nacelles, as well as trimming the tabs on the side of the fans.
Before proceeding I am going to wait and hear from Tam. These fans feel very good and stout, though I have nt run them yet. With this Skorpion outrunner on them they would have no probelm pushing the plane around, BUT they feel heavy. I have not weighed them, but I bet they are near 1.5 to 2 pounds each, which is a lot of weight to add to this model, by the time you put 4 servos in the tail.
Too many questions.
BTW, which servos are you recommending for the elevators? flaps? ailerons?
Keep up the good work.

Ron101

My Feedback: (22)

Doc,
not to be a kill joy but over on RC Groups in the EDF fourms
there has been a few threads on the Ramtec and many on the Dyn-e-max...

it's seems that the higer pitch of the Ramtec makes it really draw high amps... where did you get those? are the home brewed of from retailer?

For this project if it was me I'd only run the Stu Max or the TJ-100
not that the Dyn-e-max of the turbax aren't good fans ... but with the extra weight of a twin and the higher amps draws of those fans you flight will suffer

I really don't think you will be happy with those fans in this nice plane.. I'd guess a 3:00 flight on 5000mah packs with those fans drawing up close to 120 amps
The Dyn-E-MAx does much better with this motor pulling around 95 amps and 4400 watts

Ron

cgrcjet

Hey Ron
I just got back from san jose. If i had your number i could have stopped by on the way back down. What kind of aircraft do they have in your museum up there? I always thought about stopping by there all the times i have passed through.

On the other hand, Tam called me when i was halfway back home. I could have stopped in at his shop if he had called an hour earlier. We discussed fan and wheel setups. He will be sending me down a fan so i can start on the mold for the inlet. He said his fan weighs in at 1.3lbs, 6s I believe 1.6lbs x's that by 2 and you get about 6 lbs. Our turbax setup is about twice the weight and accounted for just about the other half of the weight of the A10. He said the exhaust is good at about 75mm on his fan.

chris

Shaun Evans

Ron,

3 minutes??? Don't your numbers on the Dyn-E-Max assume you're flying full-throttle all the time? Just one of those fans would take off and fly this airplane. The E-Turbax equipped one flies at half throttle! Not every jet needs to be a paper airplane to fly nicely. This bird flies and glides BEAUTIFULLY with the twin E-Turbax setup, so the added weight of the Dyn-E-Max setup would scarcely cause the airplane to fly badly. Saving some weight and adding a minute of flight time would hardly be worth the realism you'd lose (sound-wise) with the TJ setup. At some point, what's the point of having a scale jet if it sounds so unrealistic? The Stumax sounds GREAT and the Dyn-E-Max sounds AWESOME.

tamjets

My Feedback: (2)

After Ohio E-Jets and Fresno. I'll get this A-10 project going.

cgrcjet

All a matter of personal preference. The turbax setup did fly half throttle. I will let you boys decide. Other than that, we should hopefully have one flying with tams fans in about a month or so ,so we can see how it performs.

thanks
chris

Shaun Evans

Chris,

Preference....of course. I don't need to wait a month to guess how it will fly with Tam's setup. The performance is certainly there with his fan. No doubt about that. When I build mine, though, I just prefer to have a more realistic jet sound since that's available to me. I'll save the high-pitched electric sound for sport planes and go with something more "mean" sounding on a Hog...

tamjets

My Feedback: (2)

What ever my fan sound like. But one thing for sure it sound much better than your mouth and your @$$.[sm=lol.gif]

Shaun Evans

Tam,

Grow up, will ya? We're all entitled to our opinions, right? I just wrote that your fan has good performance. To me, it sounds like a mosquito on crack and I wouldn't want it in a scale jet. If I thought the opposite, I'm sure you wouldn't be replying with childish (and barely legible) wisecracks.

Who helped you write that one, anyway....? Now run along and go 'reverse-engineer' another German fan or something before you get your feelings hurt in here, big guy.