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Hobbies Collectibles vintage gaming SNK Neo Geo Move Lists & Game FAQs Real Bout Fatal FuryUtility of a governor, and throttle curves
- Details
- Category: Techniques
- Published on Wednesday, 08 September 2004 00:00
- Written by Administrator
- Hits: 7020
by Steve Simpson
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> 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
situation.
Are we having fun yet?
A governor eliminates the need to worry about any of the stuff in
this post . .
History and advices to novices
- Details
- Category: Techniques
- Published on Thursday, 02 September 2004 00:00
- Written by Administrator
- Hits: 11654
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 1500⬠!!!!! but know I recover my mind, and exchange all parts, gaining 5% or less with a better exhaust at 120⬠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)
Tips :
- Flying heli is fun, but it is even better if you fly a cheap and easy to repair heli, forget high-end heli with lot of upgrade or carbon frames, forget 60 size for everyday flight.
- Choose upgrades that can increase SECURITY of your model and persons, nothing else. Upgrades part can break or usually bend in a crash (metal swashplate....)
- You can increase security by only changing some parts in your heli or following some advices/tips from experimented pilot or forums.
- A crash can occur at ANY TIME, don't play poker with your life ! always sacrify the heli ! it is just a mechanical toy and you can buy many parts to repair it, it is not the case for your body or for replacing killed people.....
- Cause of crash in increasing order : external events (birds, collision with airplane) -> mechanical failures -> radio glitches -> pilot MISTAKES
Comment prendre soins de vos accus.....
- Details
- Category: Techniques
- Published on Wednesday, 01 September 2004 00:00
- Written by Administrator
- Hits: 7857
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 :
- Des packs "inlines" ou "racing" uniquement (résistances totale moindre).
- Pas de pack zappés (moyen d'augmenter artificiellement la capacité et de diminuer la résistance interne en
envoyant 1000 A ou plus en impulsionnel ds chaque accus). Les fabriquants ne garantissent pas la fiabilité ! - Pas de nimh sur un helico 24 elts, pas d'applicaion ou plus de 20A sont demandés (peut être dans le futur)
- Préférer des NiCad plus rustique mais plus tolérant face aux erreurs et brutalité que vous leur ferez subir. Si possible des RC2000 ou RC2400
- Accus SANYO :
| 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" AE, SCE |
| Standard | Les moins chères. AA, A, SC |
Montage :
- Sur un helico, ne pas utiliser le BEC, utiliser une alimêntation séparés, moins de pertubations et plus de sécurité.
- Des fils de batteries les plus court tu auras...moins d'interférences a subir.
- Les fils du contrôleur au moteur aussi court que possible, mais attention certain brusless (kontronic) ont emaillé leur fils...a poncer avant de souder. C'est la source no1 d'interferences hautes fréquences.
- Des prises PK dorée a l'or d'au moins 4mm de diamètre et de qualité (Ã changer des que l'on voit le métal ou si
elles sont oxydées/rouillés) - Récepteur FM (PPM) pour voir si le montage est sain et sans perturbations (interférences) mais après préférer un récepteur PCM.
Maintenance :
- utiliser un bon chargeur ! la securité du modèle en depend !
- Stocker les batteries déchargé et non chargé et dans un endroit frais (frigo mais pas congélateur) pour réduire
la réaction chimique interne. - En cas de crash, les démonter et verifier les connexions.
- Les cycler toutes les 5 decharges.
- Ne pas les jeter par terre ou les stocker au soleil dans la voiture ou les tenir par les fils....
Charge :
- Les peaker (chargeur delta peak, ils le sont tous actuellement) juste avant de voler pour rattraper la chute de tension (7,5% en 6 heures)
- Varier les courants de charges pour prolonger leur durée de vie :
- charge rapide sous courant fort (4 a 5C) : pour avoir une décharge rapide des élements sous un courant plus fort, en fait
de la pêche mais moins longtemps.
- charge lente (C/10) pour une décharge plus lente, courant et tension debité sera moindre mais temps de vol allongé. - ne pas équilibrer les pack (décharger une a une les batteries ds un resistance ou par court circuit)! sinon l'helico peut chuter
d'un coup par un manque subit de puissance - ne pas les charger chauds, les placer sur une brique froide de camping et/ou sous un flux d'air
Décharge :
- Ne pas les laisser se décharger completement, dès le 1er signe de faiblesse, se poser...
- Fabriquer un canal de refroidissement forcé (ventilateur de pc suffisament puissant), voir mes photo
Tips :
- Méfier vous comme du diable de l'hélico, une fois la partie puissance branché, le moteur peut démarrer n'importe quand !
Li-Ion:
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)
If your heli do not have enough power....
- Details
- Category: Techniques
- Published on Thursday, 02 September 2004 00:00
- Written by Administrator
- Hits: 7402
- Adjust your pitch curves (too much ° pitch asked ?),
- Adjust your throttle curves,
- Add more nitromethan, try 15% then 30%, but be careful of the fuel price and lifetime of engine!
- Switch for an exhaust pipe, (Hatori...) +5 to +7% increase
- Use smaller blade, (505mm instead of 550 mm),
- Change for a better motor, (OS46 or OS50 instead of 30''size)
For more basics advices, search for FAQs on internet, a lot of documents has been already written.....
3D moves and tricks
- Details
- Category: Techniques
- Published on Wednesday, 01 September 2004 00:00
- Written by Administrator
- Hits: 11643
