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Darrell,

Any updates on how this project is coming along?

Darrell B.

Well, progress has slowed to the point of waiting on the company that I ordered the motor and ESC from to send them to me. I have placed an order with HOELLEIN, a wholesaler in Germany. Thy were waiting on the ESC from the manufacturer, and said that today they should be able to ship my order. I only hope that things don't get hung up in customs or anything like that!

I have e-mailed back and forth with the guy at Maxamps and he is willing to build my battery from their 2250mAh cells for $20 per cell. I am still leaning toward Thunder Power or Tanic. I haven't heard anything about the Maxamp battery performance under these kinds of loads. Has anyone around here heard about them?

I will post up some pictures of the plane after I get the motor mounted. It is kind of hard to give birth to it when you don't have a heart to place in there.

Darrell

luc-RCU

maxamps cells are ok, same type as polyquest, Tanic, Irate (which I use on my conversions in 6S2P 2200, 8lbs planes)...Brian is a nice guy too.The only better cells now (really better, to be seen in voltage under load) are in my mind the new TP pro lite, but price is different. Try to have some kind of tabs and balancers to get a long life out of them...

Darrell B.

I saw where someone in Germany had all of his packs set up so that he could charge them by parallel pack. In other words he could charge them as a 1s4p pack. Is this what is happening when the packs are made up with taps? It makes sense to me that you could charge them this way.

Darrell B.

luc-RCU

All my packs are done (I did them) in xP (in fact 2P). I can discharge them in serie with a multiplug or charge them in serie or // (with another multiplug)

Darrell B.

Thanks for the pictures. that helps a lot.

Darrell

Darrell B.

I have to appologize to everyone for taking soooooo long on this project. I wish that I could just pop them out like some of you are capable of doing, but in my case I'm wainting on funds to move on to each next step. I thought that you would be interested in some pictures of the motor and installation. I only have a 3s 4500 pack to try out this motor with so far, but my first impressions are that this is a sweet motor.[8D] I only hope that when I can afford my flight pack that it will run just as well on 10s.

I used several of the stock parts from the kit motor mount for mine. Why invent something all over again. I also took a que from the Wema Flyware picture of their prop adapter and used the spinner backplate for one of the parts and a 5/16 fender washer for the other. Add four 4mmx30 bolts and the prop adapter was finished. I borrowed one of Greg Covey's ideas for the PVC spacer and used 1/4x20 all thread unstead of bolts to try to keep down the weight some. This mount is very sollid!

Darrell B.

Here are some more pictures.

Darrell B.

I know that I had a picture of this earlier, but it was a static picture, and this one with the motor installed just looks even better.

I did some taxi tests in the drive way, and slow taxi on concrete is achieved easily with only 4 clicks of throttle. The plane handles quite well with very good throttle response on the Jetti 77. I'm looking forward to seeing how much Hobby Lobby will be asking for the 90. I really think that I'm going to need it to be able to take this motor even close to its full potential.

Good Luck to all,
Darrell B.

Greg Covey

Darrell,

Your P-51 is shaping up and looking great! Any problems encountered when mounting the aluminum spinner or prop?

The new Jeti 90-amp ESC will be available from Hobby Lobby soon for only $249.

Regards.

Darrell B.

Greg,

I did some designing, based on the prop adapter that Flyware puts out for their motors. All I could get was a picture from their website, but what it looked like, was two 5/16 fender washers and four 4mm bolts about 30mm long. So I went to Lowes, I don't have a Home Depot close, and did some shopping. When I got home I made a rubbing of the front of the motor to get the spacing and general layout for the bolt holes. Then I measured the rubbing, and transfered the measurements to the fender washer. I drilled four holes, and made sure that the bolts would go through them and into the front of the motor. I used this washer as a template to mark and drill the spinner and prop. Then it was just a matter of a little filling to make everything fit. Talk about a solid and positive way to mount a prop. The spinner is knurled on both sides so that nothing is going to try to slip anyway, but the four 4mm bolts realy tie everything together nicely.

I'm still shopping for batteries. I was hoping to come in under $600, but so far the best I can do is closer to $700.[] When do you think that these new batteries you talk about will come to market? Do you have any experience with the MaxAmps batteies? They sure have an attractive price, and their discharge rate is nice as well.

Best Regards,
Darrell Button

Greg Covey

Darrell,

It looked like you had a fair amount of work to mount that prop. It is an unusual configuration compared to the glow engines or other big outrunners. Did you have any balancing issues or is there a center shaft on the back of the prop for alignment?

I'm not even sure what MaxAmps batteries are. For the new Kokam 3.2AH cells, I roughly estimated about $45/cell or $450 for a 10s configuration. The 6.4AH pack in my Edge 540 is about $900. The new FMA SKYVOLTS packs should be out soon. I will know more next week.

Regards.

Darrell B.

Greg,

Thanks for the information about the batteries. I look forward to the Skyvolt information.

As for the prop, I was really releived when the largest spacer ring that APC includes with their props fit over the short shaft that comes out of the front of the motor perfectly. This gave me a very acurate centering of the prop. I balanced the prop after I drilled out the four bolt holes, and had to do verry little sanding on the back side of one tip. I also ballanced the spinner back plate since I drilled four holes in it as well and found that the ballance had not changed any. When the motor is running everything is turning true and smooth. I was tempted to not space the spinner out as far as was recommended for the gas motor but I figured that if any air was able to get through it would help with cooling. I need to add some baffles to direct the air from the scoop up and swirl it around the motor and ESC. The cowel has a large hole cut in the bottom for a muffler that will work well for an outlet. I'm still debating about battery cooling. If I use a large enough mAh battery so that my burst amps during flight, is only as high as what the battery's constant current rating, I shouldn't have any cooling issues. What do you think? Any way, I'm getting very excited about finishing this project and getting it in the air. I only wish I knew someone with a digital video camera so that I could post it here. I still need to set my control throws, range check, you know the usual last minute items. Thanks for your interest.
Good Luck,
Best Reguards,
Darrell Button

Darrell B.

Help!!

Can someone suggest where I can find an 8mm or 5/16 Wheel Collar? I tried drilling out a 1/4 and couldn't get the hole centered.

thanks,
Darrell B.

Darrell B.

Well I solved the wheel collar delima by driling out one that was 1/4". It works well.

I have made my mind up about batteries. I'm going with the MaxAmps 2250 cells made up into two 5s4p packs. This will give me the weight I need to ballance my plane. At 9000mAh this should give me a very nice flight time. It looks like RPMs are going to run in the 6500 range. I was hoping for 7000 and may still get if when I get some real batteries and not the ones I'm using for test runs. I am going to try to get the cells made up into a brick of 4 cells tall and 5 cells long with all of the tabs facing one direction. I hope that they can do this, it will really help with the fit in the airplane and allow for some movement forward and backward so that I can tweak the CG.

Does anyone know of problems with packs made up into brick shapes? What I mean is do the middle cells overheat? I'm just wondering.

Good Luck to all,
Best regards,
Darrell B.

luc-RCU

no much more than any other shape... If you awant to avoid heat, I would suggest, with such a big amp packs (9A) that you split your glights. That will help cool down the cells between 2 (or more) flights. Lastly, avoid discharching above 80%, for safety margin, imbalance problems as well as heat.

Darrell B.

Sound advice, Thank you very much.

Darrell B.

Darrell B.

Well, I took the plunge today and ordered two 5s4p 9000mAh packs from Max Amps today. They have some really great pricing, and from what I'm reading on RCGroups really good customer service. These packs are rated for 12C continuous and 135Amps burst. That should be more than I ever will need, especially if I break up the flight to say 8 or 10 minutes long. Now if I could just lay my hands on two of the Astro 109 chargers. Everyone is out of stock, or they want way over sugested retail for them. I'll post some pictures of the packs, and how they fit in the fuselage, when I get them. I ordered them in a brick configuration to help with balancing my plane. I really don't want to have to use a flight pack for the radio, and don't want to add any weight to the tail for balance. With these batteries, I'm still looking at my 20# AUW as a reality. This would be great, because that is as good or better than what the other gas planes are coming with large motors on them. Oh, did I mention that the T-Rex 40 is capable of 5 horsepower. I don't know if this specific wind is, but I went with the hotter wind for more rpm at the prop. More to follow. With any luck, this plane will fly in June.

Good luck to all,
Regards,
Darrell B.

Greg Covey

Hi Darrell,

Do you have a link to the Max Amps site you mention?

Thanks.

Darrell B.

Greg,

Here is the link to the Max Amps site.

http://www.maxamps.com/


I ordered the 2250mAh Cells in two packs. Each one is a 5a4p configuration. Total pack size will be 10s 9000mAh. This pack should be able to sustain over 108Amps continuous and 135Amps burst.

Best Ragards,
Darrell B.

jfassino

Any update on this project?

Jim

Darrell B.

Jim,

Thank you for your interest. In the post above yours you see that I ordered my battery packs from MaxAmps. They sent me an E-mail yesterday and said that my packs were going to be built with a new 15C cell that was coming in this week. WOW! It seem like every time that they get in a new batch of cells something has improved about them. The last time it was the voltage level under a load, this time it is the current draw. What is next, half the weight?

Any way, I'm getting excited about flying the Mustang. I don't think it will be a speed demon, maybe 100mph WOT, but I think with the 24" prop, and a strong power system, it will have a great climb, and be very aerobatic. I think nice scale flying at half throttle, and 20+ minute flights should be the ticket.

I'll post back here as soon as I get the batteries, and take some power readings.

Good Luck to all,
Darrell B.

jfassino

Darrell,

Did you consider a four bladed prop. I saw another thread with a gas conversion to four bladed on this TF Mustang. I would think with the flexibility of electric systems this might be an option. I wanted to follow you project and would consider this as my winter project and would get even more excited by a more scale prop.

Thanks for the update and sharing.

Jim

Darrell B.

Jim,

I am considering the new prop drive being manufactured by Warbird Propdrives as a possible solution for the 4 Bladed prop question. If their unit proves itself, Flyware makes two sizes of the T-Rex motor, the 40 and a 20. Both of them are available with a higher Kv wind. I would probably lean toward the 700Kv version, and then let the gear reduction do its thing. I think that with a 4 bladed prop it will take more amps to fly because of the lower efficiency of the prop.

My other idea is to buy one of the Solo props with adjustable pitch blades, and then design a simple belt drive unit myself. As you said, with the flexability of electric power systems, there is no limit, especially with battery technology improving as fast as it is. From what I hear, belt drives are quieter than gear drives.

Good Luck with your project, I'll keep you posted on this one.

Darrell B.

Darrell B.

Hi everyone,

I'm taking a few final pictures before I fly the mustang. I want to document it in case it is it's first and last... well you know.
I should be able to get them posted later today. I would love to have one of the CC HV 110 controllers to put into this plane,
but no one seems to be able to ship them right now.