Official Freewing 90mm F-15C Eagle Thread

[purduephigam]

Smooth is important ,especially coming out of the fan.

I'd consider:
Get stiff paper and make a fairing from back of the fan housing to the ID of the LEDs, harden the paper with thin CA Then thin stiff clear plastic from ID of the LED ring back to meet the foam efflux tube far back as you reasonably can, with holes for the whistles to stick in.

I also suspect that plane violates the 80% to 85% FSA at the tailpipes rule.

I feel like I've complicated matters with this setup. I didn't realize they make smaller twin LED rings. Maybe I should've just looked into this. I could remove the exhaust nozzles and cut to fit and this would avoid any airflow complications. I'm a little paranoid to get this up now, even with the fairing modifications. Do I go back to the drawing board?

[purduephigam]

I usually drill holes in the foam deep enough to seat the whistles all the way to their shoulder. How did you secure yours?

I tested them at different heights. Started out seating them completely, but found the sound wasn't what I had wanted. Incrementally moved them up until I got the desired sound. I just used foam filler to secure, and attempted my best effort to keep the lines smooth. Hope this works.

[fhhuber]

Smooth is important ,especially coming out of the fan.

I'd consider:
Get stiff paper and make a fairing from back of the fan housing to the ID of the LEDs, harden the paper with thin CA Then thin stiff clear plastic from ID of the LED ring back to meet the foam efflux tube far back as you reasonably can, with holes for the whistles to stick in.

I also suspect that plane violates the 80% to 85% FSA at the tailpipes rule.

[RCjetdude]

I usually drill holes in the foam deep enough to seat the whistles all the way to their shoulder. How did you secure yours?

[purduephigam]

Here are some pics for the LED and whistle mod. I'm a little concerned with air restriction negatively affecting thrust. I tried to smooth everything out with some foam filler. Does anyone happen to know any thrust values for the high performance version? I have a digital fish scale I could use to determine force, but without having done it beforehand, I don't have anything to compare it to. I talked to Wayne at MRC and he said I should be fine. What do you all think?

Finishing touches on this bird will involve some weathering with the airbrush. I'll get more pics up when it's finished!

[fhhuber]

I'm wondering if I can get away with using a pair of the admiral 40c 4s 5000's in my 8s setup instead of the 60c pro packs. the 40c batteries weigh 482 grams, and the 60c ones weigh 500 grams. But the 60c have 10awg wire, and the 40c 12awg wire. Any thoughts ?

You'l see slightly lower max power. Not much. (hard to measure without a wattmeter)

I have been running 25C packs in my Freewing F-14 with no issues.

With the lighter wire you'll have to pay careful attention to the solder joints between wire and the connectors. On a 12S 105 amp model I dodn't pre-test one set of packs and the power through the wire melted a flawed solder joint resulting in loss of power appx 20 ft altitude on takeoff. (fortunately I use a separate battery for RX, not a UBEC for anything 6S or higher, so I had control for a fast landing)

[scootergenie]

I'm wondering if I can get away with using a pair of the admiral 40c 4s 5000's in my 8s setup instead of the 60c pro packs. the 40c batteries weigh 482 grams, and the 60c ones weigh 500 grams. But the 60c have 10awg wire, and the 40c 12awg wire. Any thoughts ?

[gooniac33]

I trimmed the cheater grate to allow it to sit flush around the esc. Have a question though....anyone know what size afterburner rings will fit in the nozzles ? The 64mm size from rc castle are 75mm outer dia. but the inside dia. of the nozzles is 69.36mm so those won't work.

I did the same sort of thing on my F-15 since I used a much larger than stock esc.

[gooniac33]

Hey guys,
Dumb question here..
I have the stock pro PNP with the separate UBEC. Never had a separate UBEC before. I'm assuming it's to power my receiver? Any issues with it on the stock 6s setup? I see a lot of people changing it out with 8s setups.
Thank you for any help!

That is a legit question....

People switch to 8s for other reasons. Not the UBEC.The UBEC is used for powering the RX which in turn powers the servos, retracts and lights on the plane. The stock one has worked great on my F-104 for over a year now. I use the ZTW 10amp UBEC in my plane since I have a different ESC than stock.

[purduephigam]

I'm out of town until Tuesday but I'll try to get some pics up next week. Hopefully I'm not berated for restricting airflow (had to adjust the height of my whistles as well.

[scootergenie]

It never occurred to me to put a single ring behind the fan. Sure would make wiring a whole lot easier. I like that idea ! Yes. Please post some pics of your mod .

[purduephigam]

I trimmed the cheater grate to allow it to sit flush around the esc. Have a question though....anyone know what size afterburner rings will fit in the nozzles ? The 64mm size from rc castle are 75mm outer dia. but the inside dia. of the nozzles is 69.36mm so those won't work.

I actually used the 90mm and cut out some of the foam behind the fan. Doesn't seem like there's any airflow restriction based on placement. I could get some pictures if you'd like.

[RCjetdude]

Bill (urrl) should know what works.

[scootergenie]

I trimmed the cheater grate to allow it to sit flush around the esc. Have a question though....anyone know what size afterburner rings will fit in the nozzles ? The 64mm size from rc castle are 75mm outer dia. but the inside dia. of the nozzles is 69.36mm so those won't work.

[Phatbob]

Thank you guys !!

[RCjetdude]

No dumb questions.... When going from 6S to 8S many 8S and up capable ESC's don't have an internal BEC built in so it is necessary to have a separate BEC or some other suitable power source for the receiver if that is the case. I have an 8S setup but the Castle Creations Talon 120 HV ESC I am running does have an internal BEC so I am using it. If your set up has a separate BEC it may be because the ESC doesn't have one internal, or it may not have been powerful enough for all the loads so a bigger one was needed.

[bill34207]

Hey guys,
Dumb question here..
I have the stock pro PNP with the separate UBEC. Never had a separate UBEC before. I'm assuming it's to power my receiver? Any issues with it on the stock 6s setup? I see a lot of people changing it out with 8s setups.
Thank you for any help!

The reason you see people swapping them out on 8s setups is that the stock BEC was not designed to operate above 6s voltage
Just plug your's into the battery port on your receiver.

[Phatbob]

Hey guys,
Dumb question here..
I have the stock pro PNP with the separate UBEC. Never had a separate UBEC before. I'm assuming it's to power my receiver? Any issues with it on the stock 6s setup? I see a lot of people changing it out with 8s setups.
Thank you for any help!

[Phatbob]

Looks good! I'll be doing the same if the lights ever get here.

[purduephigam]

Little addition to my F-15. Spent a lot of time feeding aluminum tape! Also managed 4 Vortex Howler whistles. Looking forward to getting this up (when it's not 2* outside).