First build ever, EA Photon

[BodgeIt]

Well, I took the plunge. I have added a small undercambered section to the wing tips, to hopefully provide some gentle stall characteristics and nicer handling at slow speeds. Tomorrow should be maiden day!

I have to center the servos, bind the reciever, double check the CoG, set up my ESC and Low voltage alarm and then hope for the best! Very excited. I will be sure to get some pics before and after the maiden, and possibly a video if I can convince my dad to video it.

 

[Craftydan]

Do glide tests first.

MANY glide tests, until you feel confident everything is trimmed and balanced right. If she won't glide well from your hand, adding power will only make her behavior worse.

Point her into the wind, trimmed, balanced and live (remove the prop -- no sense tossing it just to break it) and give her a strong level toss aiming just above the horizon, and gently control her down. Trim and toss again until she needs almost no help from you at the controls. Balanced and without motor power, she should glide a good 10-50m with a good toss, depending on how cleanly you've built her, and how well she's trimmed, so don't worry about giving her a good toss -- the distance isn't nearly as important as how gracefully or how dramatically she finds her way to the ground.

Good luck

 

[BodgeIt]

Thanks for the advice Dan. I did 3 or 4 glide tests with no prop and it was balanced really nicely. It didnt glide far, maybe 10m, but I think im fairly heavy due to heavy foam board and inefficient build technique. I didnt give it enough power on my first 'proper' throw, and it stalled and landed a bit heavy on the front and my prop saver came off (I didnt do the screws up properly) so that ended my day. I also think I need to throw harder, as I was throwing really gently for some reason. I will admit I was very nervous, so technique etc was awful. For next time:

-Throw harder
-Ensure prop is good and straight
-More throttle on launch.

 

[BodgeIt]

So, maiden done! I flew it properly today at a local field. Unfortunately, I bent it quite badly (ha!!) but nevermind, its my first plane so I kind of expected that to happen.

I had really, really bad trimming issues where it would roll itself to the left no matter what I did. It also did not fly straight, no matter what I did with the rudder. Both of these things lead to a relatively short (10 mins) of flight. She crashes well though! One crash I came in so hard that I dug a hole in the mud with the prop, quick wipe down and she was good to go. The airframe itself is a write off, though the electronics seem ok so I will use those on my next build. I have a huge amount of respect for you guys, flying is hard!

If I can get hold of a printer I will have a go at building a storch, as it seems a lot slower. Even the photon seemed lightening fast to me so I need to take it easy until I am better. Im also designing a f22 but again, that can wait until I am better.

 

[BodgeIt]

So after talking to a friend who flys full scale, he asked to see my plane. He revealed a few problems (in the excitement of building and flying I overlooked these):

My ailerons were not sitting level with the airflow, thier 'resting' position was 30-odd degrees down so they were acting like flaps.
My vertical stablisor wasnt straight
My elevator push rod was moving as my z-bend wasnt quite right, so after a minute or so pulling up would only get 5 degrees of movement.

These things pretty much condemned the flight in my opinion, so at least I have an excuse for being so bad!

 

[Craftydan]

We all have an excuse for being bad pilots at first . . . we've never done it before

learn, rebuild and eventually you'll get that coveted "second flight". The bits of hands-on advice is worth it's weight in gold -- might be good to get a preflight from your friend . . . then have your buddy take a few pics of your successful flight

 

[510thousandths]

Try again, and again, ..........and again...Eventually you stop buying props a dozen at a time because one last for 2 flights, then 4 flights, then 10...
The bad news is, once you can put it in the air, bring it down (on purpose and where you want it) and get comfortable, then you'll want to expand you fleet! It is an addictive hobby.

 

[BodgeIt]

Im already addicted! I am currently building a slow stick (Scratch build, couldnt afford a kit) and another photon (but with a 8' wing chord, not 5). Going to try and make it a little slower but most importantly, built properly!

Edit: my wing loading (cubed) is 7.2 with the 5 inch chord, so I am going to leave it as it is. I think its just the ailerons acting as flaps that caused me to stall so much and be so slow.

 

[BodgeIt]

Ok, for the moment all builds are off. I weighed my photon, and all up weight is 1.2kg - ed's build is 850g all up. Is this going to be a problem? I know the foam I have used is heavier than others and Im now wondering if my 'underpowered-ness' is down to the weight of it. I might buy some depron and build with that instead as I need the plane to fly relatively slowly and at the moment it takes full throttle to maintain height.

 

[510thousandths]

wow! 1.2 kg!, that heavy, dude! Ed has a bigger motor and battery than I use, so that explains our difference.

How to make it lighter...Yup, depron will work, but it is fragile. Maybe cut out alot of the foam in stratigic areas like holes through the fuse. Or...better yet...take a vacation in the US, buy a crapton of Adams foam board, load it into a cargo container, put it on a ship to the UK and build forever....

OK...maybe cutting hole would be easier. Or try a 6" airfoil...Thats going to cut quite a bit of weight as well.

Rather than using Eds noob tube, make the fuse with only 3 side, "omit the bottom", put in a couple formers to keep it sqaure and tape the bottom closed.

Or, omit the tape on the wings and fuse. It's not as needed on your foambaords as it is on the Adams foam board where a sneeze will make the paper to get soggy and delaminate.

 

[BodgeIt]

I did think about the 3 sided fuse, but a) the fuse itself only weighs 220g (so in the grand scheme of things, not a huge amount of weight saving... 45g?) and b)the drag from all the servo wiring, servos etc might counter that whilst in the air. My wing is the heaviest foam peice at 440g (5" chord). I might look at pricing for a job lot of $ tree foam, if I buy a years worth it might be do-able. Can anyone give me the length, width and weight of a single board?

edit: had a look at other threads, seems people have already tried. I will just wait a month then go and buy some depron and start over

 

[BodgeIt]

Massive fail update : The reason it flew so terribly may also have been that it was rediculously nose heavy. Using a relatively basic cg calc, my cg should be at 4.7'' from the leading edge. I didnt know how to work it out before so it was way, way off. nearly 3 inches off.

 

[Christopher14]

Massive fail update : The reason it flew so terribly may also have been that it was rediculously nose heavy. Using a relatively basic cg calc, my cg should be at 4.7'' from the leading edge. I didnt know how to work it out before so it was way, way off. nearly 3 inches off.

I don't know how many planes I've crashed due to being extremely nose-heavy or tail-heavy, more then I would like to remember at least.:black_eyed:

 

[whiskeyjack]

BodgeIT,
Depron will work just fine. Tape one side just as Ed demonstrates and the depron will fold without snapping. I use 5mm on my depron models which saves a little weight over its 6mm cousin and a bit cheaper too. If I remember correctly the CG is on the spar adjusted to be slightly nose heavy. Not too sure about your power set up. ED used the Turnigy 2826/6 2200kv with a 6x4 prop on the model he show cased. You might at some point try that. WJ.

 

[BodgeIt]

Yup, I have just recieved a parcel with the 2826/6 2200Kv and 6x4 props. I cant fit it all though, as the shaft size is 3.17 and the supplied prop saver/collet wont work with the props. I have ordered a Reamer but that wont be here until the new year Hobbyking took over 2 weeks to deliver those bits, even with me paying £10 for postage so I wont be using them again. Has anyone built a photon as a 3 chan (ele/ail)? As adding a rudder in too just confuses me at this stage.

 

[whiskeyjack]

BodgeIT,
I hope I don't confuse you either but you are building a "Motor Glider" which would suggest you intend to fly it as a glider from time to time. Most gliders fly in their "slow flight" speed range as they soar about looking for lift. That's when the rudder is your best control for direction. Using the ailerons when flying slowly could cause "adverse yaw"; the down going aileron causes more drag than lift and instead of turning the high wing drops or "tip stalls". I would suggest you install the rudder as shown on the video so there is no need to add it later.
You can install the prop using the supplied adapter. The only thing you would change is the brake function of your ESC. Most ESC's are factory default "brake off". By turning the brake "on" the prop will not windmill and should just move out of the way on landing instead of breaking. Hope this helps.
My Photon is on the cutting bench for our Canadian build season er winter this year. Hope to have it done for spring. Good luck with yours and best holiday wishes from Canada. WJ.

 

[BodgeIt]

hi whiskyJack, thanks for your comments. I know its a motor glider, the reason I chose it as its big and stable, and as you say it should fly nice and slow. I have tried every possible combination to make the prop fit the motor shaft but it just wont, the prop will go on the shaft without any prop saver or collet. The prop savers and collet are bigger than the shaft, so it wont fit (unless Im doing it wrong.) Its New years eve and I have family round, but once they are gone I will take some pics.

 

[BodgeIt]

Yep, just checked. the numbers im listing are made up, just so I can explain my problem.

Motor shaft: 3mm.
supplied prop saver (prop mount face): 4mm
supplied prop saver (inside hole for motor shaft): 2.9mm
supplied collet thread: 5mm
prop hole: 3mm

So in any combination, it will not fit. This is beyond frustrating, I have had perfect weather, a newly built plane to fly, but no way of putting a prop on it!

 

[whiskeyjack]

There is always a way! Loose the prop saver and proceed as follows.

All you need is a round needle file. Remove the prop insert that is just a little too small for the treaded portion of the prop adapter (you will find it on the parts tree supplied with the prop). Put the insert into the prop and very carefully use the file to open up the insert until it will fit over the treaded part of the adapter. Be sure to keep the file square with the hole in the prop while you open it up.

Normally I take it down until I can gently tread the prop on to the shaft. Screw the prop in until it seats on the adapter, place the adapter on the motor shaft and secure with the prop nut. Your done! Now go fly, enjoy! WJ.