Radio controlled planes ... grrrr

[Sp!ke]

My 8 year old son had his birthday yesterday and today we went out to fly his new radio controlled plane bought by his grandfather.

What a total disaster. All I can say is this thing has the aerodynamics of a house brick. Not even a whiff of being able to climb, fly or even glide, the damn thing immediately nosedived straight to the ground at a rate of knots and broke its prop.

Now this is the 5th or 6th plane he's had and we've had a modicum of success with various types so we both have some flight experience with other planes and know the do's and dont's when it comes to model aircraft. On close inspection with this one, its design is very nose heavy with barely any thrust from the prop to maintain any forward motion so it really wouldnt be able to do much else but dive in my opinion.

£100 = about two seconds 'till destruction. Poor lad is distraught and I'm pretty furious as there is no chance this house brick would ever fly.

Fit for purpose? Nope, definately not, but how does one go about taking it back for a refund when it is now destroyed. (Perhaps this is the shop keepers insurance on such things)

I'm so sure it won't fly that I'm willing to bet the shopkeeper £200 that he can't fly the same model for more than 5 seconds.

Anyone any suggestions how should I approach this, bearing in mind I don't have a receipt (but I do know where it was purchased)?

 

[robert.saunders]

Maybe you weren't driving it fast enough?

 

[whitenemesis]

Perhaps do as you suggested (but without the bet!)

Take it back to the shop explain what happened and ask the shopkeeper to demonstrate how it should be done.

When he fails, ask for your money back, possibly he'll refuse as you don't have the receipt (does grandfather have it?) then go for a replacement with an alternative model?

 

[glojo]

I think BTB is our resident expert on this but how did the aircraft balance regarding its centre of gravity? Did you check this before attempting the first flight?

Regards
John

 

[Sp!ke]

I think BTB is our resident expert on this but how did the aircraft balance regarding its centre of gravity? Did you check this before attempting the first flight?

Regards
John

The aircraft didnt balance, I noticed how front heavy it was prior to its first flight. Its front bias could be overcome i'd imagine if the motor had enough grunt to pul it fast enough through the air.

I challange even an expert to make this fly really I do.

 

[glojo]

The aircraft didnt balance, I noticed how front heavy it was prior to its first flight. Its front bias could be overcome i'd imagine if the motor had enough grunt to pul it fast enough through the air.

I challange even an expert to make this fly really I do.

Oh dear,
I think if it were front heavy, especially if it were too front heavy then I would not have even attempted to fly it. In my days of modelling I would expect the aircraft to be able to have an ability to glide without power.

Hopefully Bill will notice this post sooner rather than later.

Regards
John

 

[BTB 500]

Hi, you called?

What type of aircraft is this? Do you have a brand name / model for me to look up? Did you buy it from a dedicated model shop or a more general toy/model shop?

 

[reflexboy]

Sp!ke-get your boy a radio controlled car...he can only damage furniture with that !!

 

[grober]

Was the aircraft trimmed for level flight before being launched?

 

[Sp!ke]

Its only a very basic plane with only the rudder requiring any sort of trimming.

One of these... http://www.ciao.co.uk/Nikko_Radio_Control_P_51D_Mustang_Air_Racer__6788695 (Looks like my dad was robbed on the price too)

Rather interestingly, All of these models on the web come with a 6v battery and yet this comes with a 4.8v battery. The instructions that came with it talk about a 4.8 battery so I'm wondering if this is old stock and Nikko changed specs because of problems like I experienced.

As I said, more power may have partially made up for the weight balance.

 

[glojo]

Found two reviews that certainly do not inspire anyone with confidence. It is so wrong to sell something that cannot appear to even do the basics.

Did the instuctions mention anything about trimming the aircraft, or finding its centre of gravity. I won't embarrass myself by saying how I used to do it because Bill has arrived and he has forgotten far more than I ever learnt.

Regards
John

 

[BTB 500]

OK. A basic aircraft like that (rudder/throttle only) falls more into the toy category really, you can get a 'Spitfire style' one from Maplin for £14.99!

http://www.maplin.co.uk/module.aspx?ModuleNo=221371&doy=22m12#overview

Assuming yours was charged correctly and the airframe was straight and free of twists it should have flown. It does sound like there may be an issue with the supplied flight pack - I would suggest getting back to the vendor ... nothing to lose in trying this.

Longer term, your son has had a lot of models. If he's genuinely interested, a proper trainer with rudder / elevator / throttle control would be a much better long term bet. Something reasonably stable and slow flying, that can take a few knocks. It may not look like a fighter, but it will be guaranteed to fly well and he'll have a chance of actually learning to control it properly (which is much more difficult than people realise).

Perhaps something like the Multiplex Easy Star:

http://www.sussex-model-centre.co.uk/shopexd.asp?id=2392

Or Graupner UHU:

http://www.sussex-model-centre.co.uk/shopexd.asp?id=22559

You can also get some very good PC simulators, which can help a lot. Multiplex (mentioned above) have a - free - downloadable one on their website, it includes the Easy Star model:

http://www.multiplex-rc.de/

Select English, then pick Downloads, Software, FMS Simulator.

You can drive it through the keyboard but you don't learn much that way! Most 'proper' r/c transmitters have the ability to be connected via a USB adapter cable, or you can get 'dummy transmitters' from about £17:

http://www.jperkinsdistribution.co....vmain=Simulators&subcatname=Ikarus Simulators

A simulator like FMS is a fun (and cheap) way to practice r/c flying any time at home. If you can fly a model reliably on a simulator you have a MUCH higher chance of success when doing it 'for real'. I have over 30 years r/c flying but still use a PC simulator to practice new manoeuvres etc. and stop myself getting rusty!

Hope that helps, just shout if you need any more info.

 

[Sp!ke]

Wow what a really fantastic post.

Looks like for a while at least he should be training on this usb joystick. I am placing the order today)

The planes you listed, can they fly in anything but a flat calm? Most planes we've had to date need a windspeed of less than 5mph or something which is few and far between round here.

 

[BTB 500]

Yes, models with rudder / elevator / throttle can handle more wind. Rather counter-intuitively, elevator controls speed and throttle controls climb rate. So simple planes with only rudder / throttle effectively only have one speed (unless they're in a spiral dive!) ... which is a big problem if there's a breeze. Calm conditions are still easier for learning because the aircraft is only doing what you tell it, rather than reacting to gusts of wind. But once you've got the basics flying in a breeze should be no problem with a plane that can handle it.

FMS is a very good simulator for freeware. I think you can switch on wind etc. in it. There's quite a community of people on the web who 'build' extra models of all types for it that you can download for free. The actual FMS homepage is here:

http://n-old.ethz.ch/student/mmoeller/fms/index_e.html

I started off with a USB dummy transmitter and FMS, then later on bought one of the more expensive simulators:

http://www.aerofly.de/

Mainly because the physics work better than FMS in extreme / unusual flight attitudes, which is what I wanted to practice. I learned to 'hover' a fixed wing plane on the simulator ... this is a very hard manoeuvre as it's an unstable position so you have to constantly juggle all 4 controls to keep it in one place. Using the sim meant I picked up the necessary reflexes much faster than if I'd only practised with a real plane at flying sessions. End result:

 

[glojo]

Hi Bill,
I note you have not mentioned trim or centre of gravity? Would you balance out your aircraft before the first flight, or simply chuck it and hope?

Regards
John

 

[comports]

HI All,

I fly models as well and as a matter of course I would also do a manual check of the C of G. MOst models should ballance at the point of 1/3 back from the leading edge of the wing.

Totally agrre with the slight sim/training method first to get the idea but it's also well worth joining a model flying club. Plenty of peopl willing to help out and especially if it's a first flight a lot of them will test it for you. Being experienced pilots, they can usually at least "Save" it if it does not really respond properly.

I also found with some electric models that the charge is very important. As BTB said, throttel controls climb rate and if there is not enough charge then their is not enough power to fly it properly.

Have you though about going to a petrol model (Trainer). They take a bit more setting up but do give a much better flying experience. The electric ones tend to be full power or off unless you get into the more expensive ones with sophiticated speed controllers.

If you were near by to me in Essex, I would gladly go out with you and your son for a flying session. I would love to brush the dust of my Heli and 6 foot wing span Eurobat.

Let us know how you get on.

 

[BTB 500]

With an RTF (ready to fly) package such as we're discussing, the aircraft comes with all the radio fitted, and generally you can only fit the supplied battery pack (we're talking about electric power here) in one place. So the CG position is going to be where the designer intended.

With any other type of model it is vital to make sure it balances in the correct place before attempting to fly it. This procedure will be covered in the instructions, and usually involves moving the battery pack back or forward. A rearward CG (tail heavy) will make the aircraft unstable and pretty much uncontrollable, and a very forward CG (nose heavy) will make it unresponsive to elevator input. Most trainers are designed to be set up slightly nose-heavy, as this gives some positive stability in pitch when trimmed out for level flight. In other words the plane will recover on it's own from a nose up or nose down attitude (given enough height!).

Aerobatic planes are normally trimmed for neutral stability, i.e. no 'self recovery' characteristics. You point the nose down, and it will follow that line (till it hits the ground ).

Moving the CG back past the 'neutral point' will give negative stability (instability) in pitch. That means the plane will randomly diverge from level flight (either nose up or nose down), with no control input ... not good for a trainer! Modern jet fighters are set up that way because it increases manoeuvrability - they rely on a powerful computer moving the flight controls thousands of times a second to keep the aircraft in check.

The aerobatic plane I'm hovering above is also set up with a rearward CG as this aids stability in the hover (like a pendulum). However it does make it quite lively in forward flight

As an experienced flyer you find out that CG position is quite subjective, manufacturers / designers tend to give you a safe (conservative) position to start with ... then it's up to you to vary it until the aircraft flies the way you want it to.

 

[A210AMG]

This is what you want...

Nitro powered goes like....will keep going after huge crashes and jumps

This is my old one as I'm currently looking at a new model

 

[glojo]

Have you though about going to a petrol model (Trainer). They take a bit more setting up but do give a much better flying experience.

I will always remember my first compression non glo-plug engine, trying to start it with the flick of a finger, boy did it hurt when it backfired. Bit of blood and ether certainly teaches you how to start these compression engines.

 

[BTB 500]

I've always had a soft spot for diesels. When I sold all my IC (internal combustion) stuff a few years ago I couldn't bear to part with these:

Both have the distinction of having been flown successfully indoors