by Steve Simpson
> Hello, I understand the failsafe issues with the Governor so that you do not blow the engine. But how much of a risk is there to actually have your engine blow up on you.
In model helicopters, there will always be some load from the fan and factory heli's tend to have somewhat conservative gearing so with a stock motor running low or no nitro as is common in Europe, it would take a pretty unusual set of circumstances to actually 'blow up' and engine.
In the US is common to have .30 size helis converted to .46 and running high nitro and tunes pipes. In this case your margin of safety gets pretty slim . . .
. and it doesn't take a lot of coaxing for certain brands to spit rods . . particularly if the carb cannot maintain a rich mixture when the RPM's suddenly go through the roof. Engine damage from over revving is cumulative though. Like smoking cigarettes. You don't have to 'blow up' an engine all at once . . . it can be done over time . . . As with bending a paper clip back and forth . . . you get away with it the first few times.
There has been a lot of chatter recently about engine damage, but the greater danger is in overspeeding the head itself. Aerodynamics will limit how fast the rotor will turn without engine power because drag increases exponentially as the airflow accelerates the blade, so there is a natural 'air brake' of sorts.
However, when the rotor is spinning up via aerodynamic power, the engine is free to really give it shove into the 'red' zone. Spitting a rotor blade is a much more serious event than spitting a connecting rod.
> What other benefits do you reap from installing
one into your heli?
One of the vexing things about model heli's up until recently was attempting to provide for some type of 'synthetic' governing of engine speed. Early on it was with interconnected linkages and later with our friend the 'throttle' curve . .. . no matter how many points there are on a throttle curve, it is still a
static curve and cannot adapt to the various conflicting conditions found different flight maneuvers. Therefore, throttle 'mixes' are used to attempt to
give the basic curve some ability to adapt to situations that require more or less power than the basic static curve provides.
Even with all these tools available, often a mix 'robs Peter to pay Paul' and fixing one situation worsens another. The more power your heli has available and the more . . . 'enthusiastic' your flying style, the worse this situation becomes. While there is always a guru who claims to be able to get 'perfect' engine speed control, the fact is that some situations that cause over revving cannot be resolved by curves and mixes. Since these setting are all static, the only solution is to have multiple flight modes where a different set of settings can be stored. Then you simply switch to that mode when you anticipate the
Are we having fun yet?
A governor eliminates the need to worry about any of the stuff in this post . .
Some of the points to consider are:
1- availability of parts (be it from your local LHS or mail order or net order (helps when you have a mishap and break something)
2- the availability of assistance (your choice may be a more problem prone then something else, so it will help if you have someone locally that has had the same problems and solved them). It also helps if you have locals who can help you with the initial heli, radio and engine set up.
3- the dependability of the units - the few problems you may have to solve with the heli (e.g clutch systems that are prone to early wear and failure, rotor heads that are more susceptible to blade flutter, engines that wah-wah, mufflers that are loud. leak and/or break, support struts that may have a tendency to break, swashplates and other parts of the control system that develop excessive play early on will still fly but will greatly increase the workload on your two thumbs and slow your progress.
4- the durability of the unit - the fewer the parts that break in a crash the easier it will be to fix and probably the lower will be the cost to fix. If brand A has less expensive parts but the lower mainframe breaks more easily then brand B then it may cost more to repair as you will have extra parts to buy.
5- the cost of parts - in conjunction with the above will reflect on the cost of the repair
6- cost of maintainance - the less dependable units will have higher maintenance costs in both money and time. The money and time spend replacing clutches for example can be considered with the cost of repairing crashes.
7- running costs - here the 30 size come out way ahead.
8- short term to long term costs - a heli that is relatively low priced and can easily be set up to be trainer stable in the hover and later be set up for hard 3D and aerobatics before wearing out or needing expensive upgrades will offer both advantages. Ditto for radio, gyro and engine /exhaust combinations
I use to have a raptor in 2000 but it has a so strong woof and poof... and since nothing seems to cured the problem (i changed so many parts in it, it cost me a lot in time and money) : as a result I do not really fly much in 2001, add the the very bad weather (it was raining everytime during week end). A friend decide to buy a moskito (he has the same problem with his raptor) and i did the same too (bought in UK for a very low price). Then a futura entered in my fleet but only for 1 months. I was too scared each time i was flying : what would cost me a crash ??. In february 2002, I buy another used raptor 30 with alot of parts for a very low price, then found the eraptor and the heaven on ebay........I will stay with the raptor and I know some pilot who now resells their futura or millenium : too expensive : a crash with a Robbe Millenium can cost you 2 raptor kit 30 ARF!
Now I must admit, that i do the same mistake as many pilot : I upgrade my machine too much. "take a good exhaust", "add a metal part here : less slope". "change this, you need better servo" As a result you have a machine who cost nearly 1500â¬ !!!!! but know I recover my mind, and exchange all parts, gaining 5% or less with a better exhaust at 120â¬ is for me now crazy: a crash and you lost everything...... so keep your raptor stock ! Robbe and other compagny should reduce their part's prices. Do not try to follow experimented pilot or people who are doing competition: they do not always pay their heli... (free from manufacturer)
Comment prendre soins de vos accus.....et de votre hélico électrique en général.
Choix de l'helico :
Un hélico taille 30 fonctionne en 24 ou 30 accus, ce qui fait deja un investissement (110€ les 12 accus). Preferer un helico 10 ou 12 éléments,,,,
Choix des accus :
|type "R"||Accus pour charge rapide, adapté aux fort |
courants de decharge et de charge.AR,SCR, RC.
|type "E"||Capacité supérieure, meilleur rapport capacité |
poids. AE, SCE
|type "U"||Rapport capacité poids encore supérieure au type "E" |
|Standard||Les moins chères. AA, A, SC|
nacheter jamais des li-ion d'occasion, (j'ai fait l'erreur) leur durée de vie ou nombre de cycle est très bas (300 fois). Symptomes, la charge se passe normalement (duréee normale de charge) mais la décharge est de l'ordre de 5 min (ex sur mon sony dscf 505)
For more basics advices, search for FAQs on internet, a lot of documents has been already written.....
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