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Old Jul 26, 2012, 01:56 PM
flying high
United Kingdom, England, Sevenoaks
Joined Nov 2011
77 Posts
Discussion
F-15 foam first time scratch build, parts list, help

hi guys well me and a friend have decided to stop flying a small delta wing plane and fly some thing a bit more bigger. weve decided on building this at some point in the next few week, ive acumilated the parts i need on ebay, found 4 sheets of grey 6mm depron and the 2x uhu por glue around 20 delivered

now i think ive calculated the 150% plans to be around 300 grams and the electrics another 500 grams, the fan/motor ive chosen stats 1.1kg thrust

ive never had to worry about these details as alway had gliders or small planes like the cesna.

any how here what i have lined up. i havent bought any thing so please correct me or direct me to some thig around the same price or unless you have a diffrent sugestion

70mm ducted fan,
http://www.ebay.co.uk/itm/1508117906...ht_3087wt_1043
uses this motor, states 1060 grams thrust
http://www.ebay.co.uk/itm/1506608729...ht_3246wt_1037
using this battery i heard zippy is good? also read 20c is about right for 3 minutes flight and 3000 mah is again about right for weight, motor recommends 14.8 4s1p
http://www.ebay.co.uk/itm/1608449092...#ht_500wt_1287

these speed controlers, thinking there both crap can get jp items if you think there better
http://www.ebay.co.uk/itm/1209341075...ht_3006wt_1037
http://www.ebay.co.uk/itm/1607075422...ht_2939wt_1037

and then this radio gear, i know its from hongkong but not found there stuff bad.
http://www.ebay.co.uk/itm/1608231933...ht_1777wt_1037

or could go for a nice
Futaba fasst 2.4ghz gear? want 6 channel for future use/plans
http://www.ebay.co.uk/itm/2511144170...#ht_500wt_1287 with a 6ch fasst rx

then for servos im thinking one of these two do i need the metel gear servos? seens as it wieghs 13.4 grams
http://www.ebay.co.uk/itm/2610723303...#ht_630wt_1037
http://www.ebay.co.uk/itm/3804511305...#ht_500wt_1054


also thought of using these rather then ply wood

http://www.ebay.co.uk/itm/1907058929...ht_1579wt_1037

and getting a buzzer. not sure how loud it would be over the planes motor, but im sure id hear it as it geos past, good this to have?
http://www.ebay.co.uk/itm/3505817616...#ht_731wt_1270


this is the plane im building, great thanks to Steve Shumate for hes plans

http://www.parkjets.com/f15-eagle/

looks easy enough to build, i have kit build experience and my friend used to build planes and gliders when he was younger.


edit forgot to ask
will this be good to fly considering its about 4 foot long and 3 foot wide,
would that 70mm or twin 70mm ducts be good?
im not fused if i crash it or i total it at some point as the foam is cheap. i can fly a plane for used to things about 2 foot long! im happy to fly it but flying stuff out the box with its own kit is easy. how does a foamie compare?
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Last edited by wanna go faster; Jul 26, 2012 at 02:02 PM.
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Old Jul 26, 2012, 06:33 PM
flying high
United Kingdom, England, Sevenoaks
Joined Nov 2011
77 Posts
any one????
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Old Jul 26, 2012, 11:44 PM
Registered User
United States, UT, Garden City
Joined Aug 2011
403 Posts
Hey WGF. I've built two of these planes at 150%, and feel that I could offer a little advice/encouragement.

I built my first one for ducted fan and I can tell you now that it wasn't worth it. It's a great plane and design, one of the best, but I just couldn't get very good performance on a fan. Maybe two could be crammed in somehow, but one fan that is big enough to give jet like performance will most likely be too big around.
You might get better performance than mine if you are more diligent about getting the ducting to the fan smooth and efficient and redesigning the inlet and outlet a little better to get the best thrust that it's capable of.
The second one I built, I used a tacon .32 on 4s 3200 mah and I had a whole new beast! It went like a raped ape! Totally fun bird. I went ahead and converted the fan job to another .32 and they fly like twins.
I am flying them with tower pro MG90's, the fly sky ct6 computer programmable 6 channel radio and matching receiver, turnigy 60 amp esc, and a seperate 8 amp ubec.
The equipment that you are looking at is a pretty good match and you should have good luck with it. Although the fan you're looking at claims over 1 Kg, I wouldn't count on it. I've yet to see an inexpensive fan put out what it's rated at.

Launching the Plane at 150% is a bit more of a challenge. I hold it by the end of the wing and give it a toss like a frisbee at about a 60 degree angle at full throttle. At such a steep angle, torque roll won't plant you!

Good luck, take picks!
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Old Jul 27, 2012, 03:25 AM
PowerTower
RWData's Avatar
United Kingdom, England, Bristol
Joined Aug 2009
977 Posts
WGF, bits sound alright, but I'd go with best radio you can afford. I'm on Spektrum & pleased with it, but there's a lot of noise about the Turnigy 9X which could be worth a look. EDF does not give as efficient thrust as external prop. Have you considered going for a pusher-prop option/conversion. HW esc's seem okay, I use them & no problems. If you don't already have one, get a watt-meter so you know before launch what your motor is drawing off and ensure you are not about to cook something mid-flight.
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Old Jul 27, 2012, 07:30 AM
Registered User
United States, UT, Garden City
Joined Aug 2011
403 Posts
I second what RWdata said about the watt meter. It's necessary to avoid frying your setup and also for getting your power / prop combo matched up for the best performance.

I have spectrum and futaba radios and I also have the flysky/turnigy 9x radio, and the flysky ct6 radio that you are looking at. I have had nothing but awsome results from that cheap radio. It's been so good that I bought 4 more and a load of receivers from hobbypartz.com and use them for my kids and training others. Only drawback is if you want to change models ( 6 model memory), you need to bring a laptop or else program the radio at home with your PC. Otherwise it is a solid , long range radio that I've never had a problem with. Perfect for budget flying!

I've noticed that the F-15 at 150% can be either a dog in the air or fast and agile, it is all about the power setup. These planes need to keep a little speed up in order to maneuver well. Hence the advice to get a watt meter so that you can optimize your power. Also if it's feasible for you to do so, you may want to wait to order your power system until the plane is built, the weight can vary and you real need about 150 watts per pound to get it to fly right if you are using pusher. With a fan I would suspect that you would need quite a bit more wattage.
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Old Jul 27, 2012, 11:03 AM
flying high
United Kingdom, England, Sevenoaks
Joined Nov 2011
77 Posts
thanks for the advice.

well ive printed off 100% and it just looks small on paper but when you consider its 6" wide 90" long and has a 66" winspan its not bad.

as for the motor ive never had to deal with them. but a 70mm won fit in the fusalage unless i deepen the sides to accomidate. i planed on using some kind of material tape inside and to taper the leading edge on the inlets. the out let wont be used as is becase i have a tube running from the back of the edf to the rear and then find out what kind of taper on the exhaust i should have, i suppose having an open end dosnt create any kind of thurst unless its tappered to increase air flow

i dont mind spending more on the radio gear just thats what i found. as for the edf or pusher im not really bothered but when i look across youtube with people with kinda the same setup they fly well.

im not set on what percentage as yet, and dont even mind cramming a 70mm in a 100 or 118% frame. even if it means redigning the top deck.

i also dont mind widing the fuaslage a little, but the ducts look big enough and i think if ive messured right the inlets are 140% larger the out let. so thinking feeding a fan wont be to bad.

i get what your saying with the pusher and to be fair it would bve easier, but i like the idea of the ducted fan being closed away,

unless i mrun some thing like this, i know it changes my set up. but looks real good, and if the set up and info is correct it states 2.5kg thurst.
http://www.ebay.co.uk/itm/Velocity-R...item1c1fe0aa47
vid at the bottom.


so i suppose the most important qestion is for a first time build (but certainly not new to building from plans) what % should i go for. its a shame the plans jump from 118% to 150% as 130% would be nice, and this is tripping me up. 118% or 150% lol

and how would i predict final airframe weight. becasue i know a single fan set up as lited abouve comes to 566 grams i think the 100% frame is 240 grams but unsure.

cheers
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