Wot Trainer

[Phil 9]

 

I added a larger 11oz tank as the suppied one did look very small. More quaility problems here though. As I tried to screw on the tank cover the captive nut the cover screws into came away fron the ply wood (chewing it up as it came loose). So I secured the cover with two screws from the side

 

I also have a larger 14oz tank that will fit in but I will see how it goes with this tank first

Edited By Phil B on 26/04/2010 13:28:43

[Phil 9]

The engine is a Saito 56 four stroke. The throttle positon on this engine ment i needed a new cable run for the snake. The standard on is suited to two stroke engines more common in trainers

 

I have not used a 4 stroke before so this will be somthing new to me. I am still unsure about proper setup . I think I will need some help to tune it in

Edited By Phil B on 26/04/2010 13:17:12

[Phil 9]

It took a bit of weight on the tail to balance it out

[Phil 9]

 

I added some trim on the wing to help with orientation and now its ready for its maiden

Edited By Phil B on 26/04/2010 13:18:54

[Phil 9]

Well I think I have the engine tuned in after running up in the back garden.

 

Just hoping for a nice day tomorrow and we will see if it can fly.

[MikeS]

Looking good there Phil.... I do like the nose wheel setup over the tail dragger. Nice build photos and info. Mine has not flown since its maiden crash. It is ready to go but needs the new engine running in. Should really go out and face the task but its my first os abc type engine and I only have some optifuel 20%?. Not sure which fuel to use.

[Phil 9]

Thanks RaptorMike.

 

I did take it to the field today but the wind was very strong and blustery so I played safe and saved it for another day.  Hoping Friday may be better ( but the forcast is not looking good)

 

As for your engine Mike what make and type is it. I have used different fuels from 5% to 20% in the same engine with no problems. The manufacturer should give recommendations for fuel. Some one correct me if I am wrong but I think the amount of Nitro in the fuel is not as important as the amount of oil in the fuel.

 

In any case I think you will need to pull your finger out and get it airborne

 

I am glad how mine turned out I am hoping this one will stay in one pice and last me a while. The added trim does not look to hiddious and with a number of these at my club I needed to be able to identify it in the air in case another one took off at the same time as I was flying (but as with my Boomerang I try to avoid this situation if I can)

[MikeS]

I agree buddy best to play it safe and not risk decking it. The engine is a OS 46 AX the hand books says 5 - 15% I think, but heli engines need more lub as they run high speed  so the lub content should be ok in optifuel 20% but I will check first. What make of fuel would you suggest as I think 10% might better?

 

Also what throws are you using?

[Phil 9]

I am by far an expert but I can tell you what I have used.

 

I have used Byron Heli fuel 15%, Model technics 10% and a ripmax 5% fuel before.

in mt OS 40 FX. Using the 5% fuel I did have quite a few dead sticks and went up to a higher nitro content on a recomendation from a club member.

 

Most at my club use a 10% home mixed fuel another member makes up and sells a lot cheeper than the model shop fuels.

 

I would recommend the 10% Model technics fuel it will run the OS 46 very well. But you could try bench running your engine with the fuel you have just to run it in a little.

[Phil 9]

There are a few tricks to maching your fuel to your engine. ie using different temperature glow plugs or longer and shorter glow plugs also adjusting the hight of the engine. But in your case it would be far easyer just to buy some 10% fuel I think.

[MikeS]

Yep I think I will get some 10% as 20% is bit keen but is fine for my Redline 53 in my Raptor. I have used model technics before and I think that stuff has a good level of castor oil in it so lub would ok.  My local hobby shop stocks it over in addlestone.

 

I might tomorrow go out and try running in the ax with the 20% to get it ready for the weekend. Not sure of the best way to run it in as I not the best with model engines as I have only been flying my raptor since september last year?.

[Phil 9]

Well I go it in the air  today and I am very pleased with the results.

 

I did get a club mate to check it over and trim it out for me and after quite a bit of up elevator it was flying nicely. the M3 nylon bolts on the U/C did not last though a rough bit of grass had them out. The idea is they break on a heavy landing but they are too week so I replaced them with the original metal ones (I will just have to take care on ladings not to rip the bottom out) M4 nylon bolts would be ideal but would require some major surgery to fit.

 

It floats along more on the landing run than my Boomerang so I will need to get used to that.

 

The only other problem to note is the enginge stalling on take off. This was due to me opening the throttel to quickly. But the engine did drag the model away at just below take off speed and I was worried I would run out of runway. Also at full throttel it did climb faster than I would have liked so I plan to cure this with some throttel/elevator mix.

[Phil 9]

I have Spectrum DS821 digital Servos. Can anyone tell me if they can be programmed to run slower. Or can anyone reccomend a servo slow module I could use for the throttel servo.

[Tim Mackey]

No they cant

[Phil 9]

Roger that Timbo

[Tim Mackey]

I should qualify that by mentioning that some transmitters of course have servo speed adjustment, which wil work on almost any servo ( except dedicated retract servos )

[John Privett]

Posted by Phil B on 30/04/2010 17:51:08: 

The only other problem to note is the enginge stalling on take off. This was due to me opening the throttel to quickly. But the engine did drag the model away at just below take off speed and I was worried I would run out of runway. Also at full throttel it did climb faster than I would have liked so I plan to cure this with some throttel/elevator mix.

 

Phil, if the engine can't cope with the throttle being opened quickly then it's probably a touch lean on the low-end adjustment.  Get one of your clubmates to help adjust it if need be, because there will be occasions when you need to open the throttle sharpish to get out of trouble - and the last thing you want then is an unresponsive engine.

 

Also, I wouldn't bother mixing any down with throttle.  If you open the throttle the plane will climb - that's what they do!  Consider what would happen if you did set up a mix.  You're coming in to land and decide to abort the approach and go around.  You open the throttle fully.  Do you really want a load of down elevator at that point, before the engine has even responded?  And similarly, what will happen if you've been flying on full throttle - with some down mixed in - and you then shut the throttle...

 

[Phil 9]

I have a DX6i TX (dont think it has any speed control)

 

Thanks John for the advice. It is a new model and I guess I will have to get used to its characteristics.

 

I do know it should climb with more throttle but it climbs rather sharpish. Maybe some down thrust on the engine mount might help?

 

As for the engine stall I will defiantly check the low end adjustment (the engine responce did seem improve as it warmed up)

[Phil 9]

Well I got it up today and ironed out the last few problems and she is now a very sweet flyer.

 

I did add some more down thrust and it is a lot better. it still climbs as you open the trottel (as it should) but at a much more acceptable rate.

 

And a tune of the engine has solved the stall problem.

[John Privett]

Excellent - good news Phil!  Thanks for the update.

[MikeS]

Well I got some Formula Irvine contest 10% today as suggsted by my club mates for the OS 46 AX. So at some point over the next few days I am going to have a go at running it in as per the instructions. etc. Cant put it off any more

[Eddie P]

Hi Guys,>>

             I have just returned to building / flying rc model aircraft after a break of nearly  11years, and not previously moved very far on from trainer stage to 2^nd low wing trainer. Earlier this year after reading good reports in your forum, I bought a wot trainer. I carried out and completed all of the suggested improvements and alterations as suggested by forum users and prepared the aircraft for flight using about 130 grms in the nose to achieve the required cg.>>

             I took her up the patch today for her first flight but found to my annoyance that I was unable to trim her out properly as she seemed very nose heavy and kept trying to dive for the ground despite putting in full up trim. I did manage to land her safely. I have rechecked every thing including wing incidence and all seems well. Does any one have any suggestions? I did install a 12oz tank and wondered if the fuel made her nose heavy. Could I safely take out some of the nose weight? ( But worried about the cg ) I am at a loss. Can any one help me please?      >>

[Phil 9]

Eddie I would say the tanks is not the problem. Mine has an 11oz tank the weight of the fuel would cause this problem.

Mine was tested by a club mate and had a similar problem of wanting to dive but there was enough trim to correct it (only just) I then had to manually adjust the length of the snake so the trims were central with neutral flight characteristics.

you will need to do the same and adjust your elevator push rod to allow you more up trim for the next flight

[Eddie P]

Thanks Phil for that. I'll give it a try. Not much up elavator  left though. Very restricted movement despite being on outer horn  hole.

[Phil 9]

That could be your problem. the outer hole on the horn gives the least amount of movement.

 

To increase the movement use a hole closer to the elevator on the horn or use a longer arm (or hole furthest away from the servo) on the servo