I know the one flown at california jets had two E-Turbax setups in it on 10s. I believe the Turbax setup is a bit over 2.5 pounds or so

So, maybe Lowell could give us an idea where the packs go tp balance the plane... If they are up in the nose as far forward as they can go, then will have any idea of what fans will work well.
I'd still for me go with the lighter fans if CG is not an issue.. I like the way lite planes fly and the longer flight times that will result from it


Ron

The link on the first page has a bit about balance.

The prototype apparently had about 6lbs of batteries under the canopy area. Roughly looking at it, I would say the engines may be a foot behind the c.g. with a couple of feet available in front of the c.g. Therefore, for each 1lb added in total motor/fan weight you would need another 1/2lb or so in the nose to balance. I am guessing that you could get it to balance with the heavier motors but I would personally go for the lighter option. I understand that the latest lay-ups that Chris is doing are lighter but the prototype was 24lbs which is reasonably fat for its size.

Model A-10s are generally notorious for balance as they don't have a huge cannon in the nose to help out. I am going to try to save every ounce at the back end to make it as light as possible. I was even considering removing the starters from the Wren 44s to help out but will probably sacrifice this for ease of operation. I have the added 'problem' that I won't have 6lbs of batteries on board to balance it all out.

This plane was awesome, i walked passed their tent many times wishing i had the loot- maybe in the near future, even if i buy the kit and hold onto it. This plane had all the fixins, and it is perfect size for me.......Nick

I have saved about 2 pounds in the airframe over the one that flew with the e-turbax setup. It probably is a little overkill for a powerplant but if you wanted a plane that screams past scale and has a more scale appearance , with the forgiving airframe i dont think there would be an issue with these fans. I would think with a glo setup you may have a few issues but with electric, the batteries will help out with that cg without adding the extra dead weight. Right now the batteries are below the rearward canopy so if need be you can slide a pack up along side the nosegear farther forward. Is dynamax using the same fan but reconfiguring it for electric? I think i was hearing about this.
thanks
chris

Thanks Chris for getting to this. I think that light is better... The new one we have now is going to be set up with a single turbine. We are still doing a lot of testing on this one guys just to come up with more options and better performance. It does fly great at half throttle with 9's or 10's at 24 lbs. I really think the lighter ones will be even better.
Will keep you all informed as we progress.
Thanks again,
Lowell

There is a few different dynamax setups going on right now.
One is from: http://www.dyn-e-max.com/fan_kits.html
I think fred's Scorpion HK4035-630KV dyn-e-max setup would work pretty well... on 12s the fan is putting out like 4000 watts around 90 amps.. it's close to 2.5 pounds
I'd run each fan on 6s

Then there is the XPS/ Jetscreamer setup that is in development.. IMHO I think it's going to work well in larger models with higher capacity packs...the fan and motor are a whopping 3.5 pounds


I'm sure Tams super light fan would also do great also.. and on only 6s per side his fan sounds really nice at the lower watt levels.. I's say that's the best setup
His fan is under 1.5 pounds

I have the Stu Max and for a scale plane it will sound amazing!! I need to talk to Stu to see how his fan will do on just 6s per fan

Lot's of ways to do it.. and most of the fans will sound good at the lower watt levels this A-10 needs with two fans
I'd say 2000 watts per side will fly it really well... but I don't think any fan can do that on 6s...

even if the plane came in at 20 pounds with 4000 watts your only talking 200 watts per pound, with a jet I really like 250 per pound but you'd need more cells which just adds more weight ...

Ron

Good info Ron. Tam is testing to find the best set up for us now. I really think he will come up with the best combo/weight/power.
We'll see...all a bit early still!
Thanks for the input.
Lowell
RC Jets Direct

Look what I picked up at the Wren open day today

Now all I need is a model to put them in

Hi,

Well, it's all about options, isn't it? I think the single turbine option is definitely worth looking into. It's been my experience that a well trimmed, well-designed model will fly great even when a little heavy. The A-10 is one of those models with the right wing planform for good performance at a fat weight. I remember the first time I weighed my first Combat Models A-10 (which has a relatively scale airframe and airfoil)). Nearly 12 pounds with a Y.S. .45 on the tail! Flew awesome, of course.

I'm definitely going to do one of these. I'm not sure if I'm going electric or turbine. I'm not interested in the Tam fans, so if it's electric, I'm going to try out the DynEmax. My suspicion is that it'll fly fantastically and sound AWESOME. Sure, it'll be heavier than others, but I bet you won't be able to tell that by watching it fly!

If I go turbine, it won't be two! I think these engines are close enough together for the offset thrust to be quite manageable. I'm sure there's an optimum thrust angle for the engine. Someone somewhere would probably know a formula....

Sean, John is putting a single P-60 in the one we just finished. It should be ready to fly next weekend or so....Look forward to having you out for the maiden. I think your right about the weight. The first one @ 24lbs. we thought was a lot. It flies great at 1/2 throttle and not a single bad characteristic. The new one is about 3 lbs. lighter. I'll call you when it's ready to go.

Sic, those engines LOOK sic!!! They are screeming for the A-10 and I can't wait for the feedback from you. That is what it needs!! We are working on yours now. I will let you know when we can ship.

Thanks guys for all the input...this is really a great project.

Lowell

Lowell,

You bet I won't miss that! I talked at length with him about the single engine thing. I hope it works! Well, I'm sure it will WORK, but I mean I hope it flies nicely. I don't doubt for a moment that it will fly authoritatively enough for people to be satisfied with the power, but I'm hoping the offset thrust will not be an issue. Please let me know when you're going out.

Sean,
It won't happen without you!
See you then,
Wex

Lowell: Please send me a pm with your phone num. I want to be in the list for the ARF version.

Thanks; Hector

Nick?!?

Is that your son in the avatar??????

What do these babies weigh in at.

chris

Chris,

The website page for the engines is here: http://wrenturbines.co.uk/engines/turbojet/mw44gold

The engines are 600g (21oz) each and put out over 10lbs thrust; I think this compares very favourably with an EDF setup. The only thing I am wondering is how easy it will be to get the fuel tanks near the c.g. At least with these engines I will only need to find room for 2 litres of fuel (1 litre (32oz) per engine).

Hey Sic

Wow! I didnt realize how compact those were. You will be saving almost a pound and a half in the engine section, over the Turbax set up in the test plane. I also weighed the latest engine nacelle pulled from the mold, and it is the lightest yet at 1.1 pounds. 4 pounds of fuel. Should not need to much counter weight as long as its fully noseward. This is getting exciting! Seems to me that the whole setup will come in lighter than the turbax. Not to mention the airframe will be about 2 pounds lighter. I am going to guess and say 20 pounds wet.

I will be bringing a few kits to John and lowell in about a week so hopefully they can get one out to you pretty quick. Cant wait to see it fly turbine!

What scheme will you be doing?

chris

I have a couple of projects on the go but will make way to get this one flying ASAP (which doesnt't mean a lot as I am pretty slow!).

The scheme I will be doing is something like the one below but without the nose art. I remember going to watch the A-10s when they were based in the UK when I was young so it has to be a RAF Alconbury/Bentwaters scheme. I am not great at painting so I'm interested to see how it all turns out.

Great to hear that the kits are coming along.

Chris,

Could you tell me what retracts and struts (type and length) were used on the prototypes?

Thanks

Hey Sic

The retracts are robart and for the mains they are Part # 631 85 deg. Retract with 1/2" dia. Straight Strut. On the prototype i did not cut the struts down. I cut the struts down on the latest one , almost about 3/8 of an inch. After looking at it they could have been cut down at least 1/2 inch total. As i cut them down i brought them forward on the mount about the same distance that i cut them down to comp. for the wheel hitting on the leading edge of the wing when in the up position.

As for the nosegear we used an airpower models 1/2 inch insert 90 degree mechanism with a robart 7/16 diameter offset strut. I am not sure the part # on these but i think it is Part # 661R for the strut. It will need to accept a 1/2 inch tire at the fork and have to offset to the right if you were sitting in the cockpit . Scissors facing rear. I did not like the airpower mechanism as much as the robart because they seemed to have more slop in them, but they did work. I would suggest Part # 638RS 90 deg. RoboStrut Ready Nose Retract Mechanism from robart for the nosegear. I believe they have the same bolt pattern. You may want to get with john or lowell for any part #'s on the nosegear to be sure.

The first picture is the first foam core wing but it gives you an idea of how the mounts are for the mains. The second picture is the new hollow composite wing.

chris

Here is another pic of the latest one after some paint.

chris

That looks incredible. Good work

The reason I ask about retracts is I am considering using trailing link legs on the mains rather than the straight Robart struts. It may look a bit odd on the ground but seeing the trailing links in action at my club last weekend I am very impressed.

I may go for the 1/2 inch Robstrut for the nose. Any reason you used the 7/16 one?

WHY Yessah Yes suh that is my son- why??

God i would love to have one of these A-10's!!

Hey sic
Very interesting choice. Not very scale looking but its your plane and if you like them and they work out fine go for it.
As for the nose strut, i believed we used the 7/16 because it is somewhat of a tight fit in the nose. Then again we have not tried the 1/2 inch strut so it may work fine. If the width of the fork is wider on the 1/2 inch i would stick with the 7/16.

thanks
chris

Nick...let's get you on the list!
Lowell