Great Planes Giant P6E Hawk--Electric Conversion

[willsonman]

No, just plug the batteries in on the YEP ESC. My ESC (old one no longer sold) does have the switch but the YEPs do not. Program a throttle cut on a switch on your Tx. If you have never done a higher-powered setup like this... be aware of a bit of spark when you connect the battery. It may startle you but it's fine.

 

[Grover54]

No, just plug the batteries in on the YEP ESC. My ESC (old one no longer sold) does have the switch but the YEPs do not. Program a throttle cut on a switch on your Tx. If you have never done a higher-powered setup like this... be aware of a bit of spark when you connect the battery. It may startle you but it's fine.

Yeah, I get a small spark when I pug in the 6-s 4500 battery on my Carbon Z so I'm used to seeing that but my Z still has a O/O switch. I was just a bit confused when I was hearing that I didn't need an On/Off switch. Is an On/Off switch just for safety or something?

 

[willsonman]

Pretty much. It's an added level that is nice and I'm surprised more of the high current ESCs do not offer it. But we buy what we can get.

 

[Grover54]

Thank you Josh for enduring all my questions but you've become a valuable resource for experience and information. I promise not to bug you too much. Have great 4th!
Jim G

 

[willsonman]

Answering questions and helping out it exactly why I post my builds exclusively on this forum.

 

[Grover54]

Ok, The build is moving right along. Here are a few pics for an update. BTW, I found a YEP 100A ESC from HK for $55. It's at my price point so I'm ordering it.
The only snag right now is figuring out "exactly" where the wood blocks are in the fuse to mount the center cabanes to. The manual offers no measurements or indications. It only says to drill holes through the mounting holes in the cabanes and to be sure to drill into the hard wood blocks just under the covering????? The cabanes are attached to the upper wing as per instructions and when I connect the upper wing to the N-Struts the cabanes sit fairly close to the fuse but not exactly flush. I can move and adjust the cabanes a bit but unless the "hardwood blocks" run a good length along the inside of the fuse I don't want to assume its a perfect alignment and then start drilling. I'm sure there are some minor placement differences from plane to plane so I'm not sure measurements from your plane will help. Do your cabanes mounts fit flush against the fuse? Comments and ideas welcome.

 

[willsonman]

Yes, My cabane struts are flush against the fuselage. You may find that you need to bend the tabs a bit. I would mark the holes for the mounting with a fine-tip sharpie and remove the wings. Then use a T-pin in those marks and you should see inside the fuselage, through the bottom wing saddle area where the pins protrude. If you feel a lot of resistance you know you are in hardwood and if you don't, then you will have protruded through the thin balsa skin and see inside how far off you are.

 

[Grover54]

Thanks, since you're Hawk was already built the previous owner may have already bent the tabs a bit to lay flush which would make sense and since this is the first assemble for this bird there's going to be some minor tweaking needed. Good idea using T-pins. Stay tuned.

 

[Grover54]

Well, the more I research and look at all the options the more questions that come up. I think I've settled on a Turnigy but it's between the Turnigy Aerodrive SK3 - 5055-320KV (65A) or the 5055-430KV (70A). Basically the same in price but the 430kv has 12T (turns) and the 320kv has 16T (turns), what ever that means, wiring?. Also the 430kv Max-Pwr. is 1750w using 5~8S batteries vs. 1630w on the 320kv using 6~10S. Are we splitting hairs?
I assume the Xoar 18X12 prop you recommended will also work with the 430? I'm ordering the YEP 80A since the YEP 100A is only available from Hong Kong and ETA is around 6-weeks. Comments?

 

[willsonman]

You cannot swing the 18X12 on the 430Kv. A 16x10 maybe. You will likely over-current the motor and burn it up. The 320 has served me very well on this aircraft. I've been able to reliably do loops, rolls, knife edge... you name it, it does it. Not overly fast but has the gusto to get you out of trouble when you need to.

The 80 A should do fine... watch out on the really hot days. Try to let it cool off between flights since you have less headroom.

 

[Grover54]

Thanks for the info. I'm glad I waited to order.

 

[Grover54]

OK, I'm following your path and purchased the SK3 - 5055-320kv w/ the 18/12 Xoar "spinning blade of death" prop. I was hoping to get in the air this weekend but I'm running a few days behind. Next weekend for sure. Stand by for the Maiden video.

 

[Grover54]

Yes, My cabane struts are flush against the fuselage. You may find that you need to bend the tabs a bit. I would mark the holes for the mounting with a fine-tip sharpie and remove the wings. Then use a T-pin in those marks and you should see inside the fuselage, through the bottom wing saddle area where the pins protrude. If you feel a lot of resistance you know you are in hardwood and if you don't, then you will have protruded through the thin balsa skin and see inside how far off you are.

Perseverance is a fancy word applied to those of us too stupid to give up! My assumption was correct, the hardwood block runs all along the inside of the fuse from the front of the firewall to mid cockpit. The "T" pins worked great to find the right position so I didn't even need to think about bending the tabs to fit flush. After all, if I had to bend them it's a clear signal they're not positioned correctly.

Final stages are installing the Receiver and Morgan Mills Battery Tray. Expecting to get the 5055 320Kv motor and YEP 80A ESC and prop on Monday. Stay Tuned.

 

[Grover54]

Almost there…… My receiver and prop delivery has been delayed till Monday but will have the motor and ESC installed today. Here's my
progress...…

Servo Test

Wings Set

Here's the hatch w/ latch for the battery access. I'm using the Morgan Mills Battery Tray and show cartridge for quick changes. Still on schedule for Maiden next week. Josh, you've been a tremendous help through all of this, Thanks a Million! Jim

 

[willsonman]

Looks like a perfect setup. Really looking forward to a flight report. Get the CG right and she will fly just fine.

 

[Grover54]

The only concern I have now is the 5055 320kv motor I decided on is a tiny bit longer than I thought and the motor mount (in it's shortest position) still may place the motor 3/4 - 1" too far forward but we'll see. It may seem funny but the hardest thing in the build process was getting the cowl right. Not sure why it was so difficult but the alignment as per the manual was a challenge. Oh well.

 

[willsonman]

I've had that issue before with these mounts. Fairly universal but you CAN use a hack saw to cut the ends off on each part to make it shorter.

 

[Grover54]

Excellent idea. I'll do that if I need to. Glad to know it's not an unusual issue. I thought it may be a "DFU" problem.

 

[Grover54]

Prop Question - I was at my local Hobby Town where they've been great resource for basic products and information. I found this Prop chart on display in their prop section.

https://www.top-flite.com/accys/topq5000a.html

I was asking them if they had the Xoar 18X12 prop thinking it would be good to have an extra on hand. They didn't carry that particular prop but based on the 5055 motor I'm putting in and considering my scale style of flying they suggested I think about a less aggressive prop like 18X6 or 16X8 which falls in the chart parameters. I explained our collaboration throughout my build and they suggested I ask you since you're obviously much more experienced. I think there's plenty of clearance using an 18 or 16 but do you think the less pitch prop is better for me based on my scale style of flying?
THX - Jim

 

[willsonman]

Well, the Xoar props are just the best IMO. Highly precise, efficient, and come pre-balanced. Worth every penny IMO. But a less aggressive prop.... Believe me, they are not considering the aircraft. This airplane had LOADS of drag. You will want the 12"pitch to get out of trouble spots. Halving the pitch will increase your thrust, yes, but you will lose airspeed... a LOT of airspeed. You will be struggling to keep it in the air. I tried a 16x10 and it was marginal. The 18x12 will suck up some power to overcome the drag but that is expected. You have a rather large frontal area, a HUGE scoop on the bottom, two wings, and struts. Plenty of drag... even without the elastic cords. While a 18x8 would give you good thrust to overcome things, you would still be struggling with airspeed... which is what you need to keep flying.

Math lesson:
32Kv motor * 25.2V = 8064rpm

8064rpm * 8 inch prop pitch = 64512 in/min = 61mph
8064rpm * 12 inch prop pitch = 69768 in/min = 66mph

so, you can quibble over 5mph all you want but if you are hauling around a 14-pound airplane you better be darn sure you have the airspeed to do what you want to do.