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HomeAircraftHelicopterMain Discussion › rev max limiter
12-08-2004 01:15 AM  13 years agoPost 41
Sceadu Abuser

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England, Leicestershire

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So when the Revmax is clipping and a sudden input is applied there must be a lag. Therefore only way to avoid this is to turn off the Revmax.

Another way to increase power with the Revmax would be to take it off and save the weight!

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12-08-2004 01:20 AM  13 years agoPost 42
Simon Brown

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Leicestershire

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So when the Revmax is clipping and a sudden input is applied there must be a lag.
If you look at the mixers Alexander uses on his machine, you will see that if there is a sudden input, then shed loads of throttle goes in aswell.
So not only is there more than required behind the revmax, but he shoves more in as it loads.

So as the revmax would need to release the limiting, along comes a kick of throttle signal to shove it up..

and if it is a fast servo too

of coarse we all realise that the unit, has to see an increase in fan speed to be able to relax that throttle servo.

that delay can maybe be looked at in the Uk when the guys get hold of them.. Over speed is something we can maybe check out..

And the underspeed has to have a slight lad if no mixers are going in at that time. Meaning the fan would have to lag, and then the revmax will relax the hold to pick it back up.

Hopefully it will be a very short time and you can try this.. But if you do not have an expensive fast servo on the throttle with your revlocks, you might have to go spend on one, to achieve the 0 lag alexander gets..

Si

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12-08-2004 01:27 AM  13 years agoPost 43
MJWS

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Airdrie, AB - Canada

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You need to make an important distinction.

Your CURVES push the throttle up... In this case constantly.

The Rev-Max responds only AFTER it senses overspeed. All lag is in an overspeed direction. This will make the heli feel more powerful as you have more thrust available. IMHO this algorythm is perfect for Hard 3d where a little extra is perfect .

The other thing to consider is that when the head is unloaded and the rev-max is decreasing throttle and lagging... You simply don't need the throttle response to be dead on. Momentum is doing it's job.

Mike

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12-08-2004 01:45 AM  13 years agoPost 44
Simon Brown

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Leicestershire

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I remain a bit confused but I am not into algarythums or whatever..
I see that the revmax is holding the over speed down.

but when hard work loads comes in, the fan will underspeed due to the load imposed.
So with alexanders setup, the revmax has to react. it has to let the throttle servo release up.

The speed in which it senses the fan speed drop, and thus tells the servo to move to increase throttle has to have the usual delays.?
I mean the only way it knows it has to react to underspeed is by a lag.

I don;t think that over speed is an issue as such as revlock and tjpro have that one nailed..
It is the underspeed during multi loading 3d that pilots want to remove.

Alexander is saying he has managed to remove ALL underspeed to 0 lag. He tends not to mention over speed, that has to be taken for granted.
We did wonder how this was done when the unit is purley an over speed unit and there are loads which come in that mixers are not a part of.

I do still feel that a unit which lets the normal curves and mixers through but reacts to underspeed and over speed very quickly, without having to have the throttle high behind it is a better prospect.

Afterall, it will be as powerful as the normal curves due to that fact that throttle input is free to get through, when cyclic and relative mixers are used..

We have the setup.. the rest has been debated and conclusions made on the other thread..
In this thread we know how it is best done according to alex..

Si

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12-08-2004 02:26 AM  13 years agoPost 45
MJWS

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Airdrie, AB - Canada

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The only way to remove underspeed is by limiting the load to what the engine can handle. Doesn't matter how we mix it, or set our curves. The only way a governor can help us is if it still has throttle it can add.

The rev-max only has to look at one simple thing. So the loop can be very tight and fast on the underspeed side. It doesn't have to correct, or respond... just get the hell out of the way. Might not be zero lag at this point, but it is as good as you are gonna get with one sensor. Once it is out of the way, it stays out of the way... so you have zero lag until it gets back to overspeed.

CSM has done the same thing by making the control loop extremely tight and fast so it can respond very quickly. Remeber we have to get gas and air to these engines and wait for a response. Being able to calculate and respond faster only goes so far. As I read it the software is already quicker than the machine and servos can respond. So the bottleneck is somewhere else.

Wish it was nice enough to put each of these units head to head. Haven't seen the CSM round these parts yet. Loved the TJ, Pro, and Rev-Max.... I'm sure the CSM will be great as well. You simply can't go wrong with any of them.

Mike

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12-08-2004 08:26 AM  13 years agoPost 46
Simon Brown

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Leicestershire

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MJWS

Indeed with the revlock on responsce

the engine is the limiting factor with the responce to inputs.
And the servo / fradio frame rate and responce time.

and of coarse with the revlock it does not wait for the lag when inputs load the heli because it uses the signal as an input..

sounds like these units have reached the limits of sensible responce now..
No wonder we all have power back to the helis..

all good

CSM has other ideas for the future.. Never done before.

obviously they arenot letting them out.. Just teese us a touch...

Bring it on..

and as for back to backs, at last we will be getting some. Ade and Gary has decided to give the test the time, as has sceadu abuser, all courtesy of revmax's funded, supplied and sent by CSm..

fair play.
Si

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12-08-2004 09:49 AM  13 years agoPost 47
Sceadu Abuser

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England, Leicestershire

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You simply can't go wrong with any of them.
This is very true; all of them will do exactly as they say on the box. It does appear due to the interest show in all these products that there is a huge market for them. Formula one car designers are looking for that extra 100/sec advantage and so it does appear we are all looking for that bit extra performance from our models. 3D flight apply’s different loads on the engine all the time sometimes it needs to be a sharp response and others it needs lots of toque. We are not only looking for something to give that extra punch but also able to extract the most power from the engine no matter what loads are on it. A formula one car wouldn’t have a chance of winning a race if it accelerated quickly but its top speed was lacking

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12-08-2004 10:30 AM  13 years agoPost 48
Raptor Rulezzz

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Rockanje, Zuid-Holland - The Netherlands

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After reading all of this I still can't see how the Revlock OR the RevMax could be "that much better" than my TJpro/9253 combo

The problem being that that one is already so darn good, and holds rpm's so wel.... ehm, what's there to improve on?

Yes I fly it to the limit, Yes every once in a while I bog the engine.... still can't see those new thingies be MUCH better... I did notice a BIG difference between the GV-1/9252 and the TJpro/9253, the latter being MUCH better.....

So just send me a Revlock and a Revmax and I`ll give honest comments, using both units on the same heli.... with the same setup, doing the same manouvres....

I`m also going with Ade that when you bump up the curves to 100% with the RevMax it basically becomes a TJpro.... Colin, you might say otherwise but I happen to know a bit how this stuff works.... and you are wrong (100% makes the limiter act like an governor, maybe a very good one.... but it`s going to have lag)

Cheers,

Rich



Proud Member of Team QuickUK, Team Duralite & Sponsored by V-blades & 4rc.nl

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12-08-2004 12:31 PM  13 years agoPost 49
Simon Brown

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Leicestershire

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Raptor Rulezzzz
After reading all of this I still can't see how the Revlock OR the RevMax could be "that much better" than my TJpro/9253 combo
Forget lag for a moment.. Re revlock and tjpro

I had tjpro for quite some time.. Fine.
A superb difference with revlock is that it picks up the throttle further down the curve like the gv-1. So it ramps up so smooth. You no longer have to slightly over cook the throttle to enusre the tjpro takes hold. I know several pilots who get times when the enging does not latch on because it might be a touch rich on a particular day etc. Nothing that you would be concerned about and nothing that a spirited flight would not sort to get the engine up to temp.
But revlock takes hold early.. VERY nice comfortable difference.

And I found the other thing was you can tell it the exact engine revs just by a setup of the lights. very simple and no need to do the calc on the website
You can set it in the field or indeed anywhere.. Accurate too.
Set to 15000 engine rpm and go fly etc.. Very nice touch..

And if you flick into a second idel up, where say the rpm is set on the revlock to be lower, it ramps down smoothly too.. Now that really is sweat.. Just so confidence building and comfortable to use.

As for lag, revlock uses a different type of sensor which must only see one magnet. Due to what ever clever new methods, it reads that magnet so much better. Even to the extent it apparently can tell which way the magnet passes the sensor.

He has a different way of writing the coding so it ends up as a combination that reacts faster to lag of the fan, but also takes more account of the throttle signal coming through and uses it.

In short, the very latest offering in the true govenor market is a faster unit due to new technology used.. We do have to see that moves forward will happen and to compare new to old can be unfair and difficult.

Revmax, well as you put, when throttle is above what it would normally be, thus above the limiter speed, the revmax will naturally limit it back all the time and release the throttle when lag occurs.

If there is 0 lag, we have to understand that revmax also has some way of reacting quicker that the older tjpro.

I think you might find that both units will give better results and more power than you have now.

I know you do not feel there is a lacking. You just try the revlock dude.. You will find, like I did, that actually there is more punch. But it is getting subtle.. only the likes of yourself that works a machine well can notice.
the majority won;t be able to tell..

Si

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12-08-2004 06:00 PM  13 years agoPost 50
Sceadu Abuser

rrApprentice

England, Leicestershire

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MJWS
After reading all of this I still can't see how the Revlock OR the RevMax could be "that much better" than my TJpro/9253 combo
Yes the TJ pro was good I have flown one for a while and it really did perform well but since then the two manufacturers have gone back to the drawing board. If you look on MA website you can see the reason for them to bring out a limiter (don’t forget they make the TJ pro so they would be discrediting their own product as well). And CSM answer was to bring out a mega fast Governor. One problem, with two solutions only time will tell for sure but it’s going to be interesting.

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12-08-2004 06:30 PM  13 years agoPost 51
JKos

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Redondo Beach, CA

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Yet another thread on RevLock vs RevMax vs ...

What I don't understand is why any of you doing these tests has not simply put a flight data recorder on your heli and gathered real, quantitative data. I would think doing so could certainly put an end to all this bickering.

The recorder from Eagle Tree Systems is available for $169.99. In this hobby that is drop in the bucket. Get a recorder and give us some REAL numbers.

- John

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12-08-2004 07:16 PM  13 years agoPost 52
TOSH

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UK.Peterborough

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No Daddy tonight...... are you 'Home-alone'?
Scarry!!!
Bugger you Russ.
lt takes months for cracked ribs to heal when you get to my age.

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12-08-2004 08:41 PM  13 years agoPost 53
Raptor Rulezzz

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Rockanje, Zuid-Holland - The Netherlands

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I know you do not feel there is a lacking. You just try the revlock dude.. You will find, like I did, that actually there is more punch. But it is getting subtle.. only the likes of yourself that works a machine well can notice.
Oke, I read your post and I can see where the Revlock is MUCH better than the TJpro (taking over smoothly etc etc.).

When I have enough $$ I`m sure gone try the Revlock (sounds better than the Revmax, hate the setting up curves.. yeah I`m lazy). And maybe I`ll try a Revmax as wel

Nice reply!

Cheers,

Rich



Proud Member of Team QuickUK, Team Duralite & Sponsored by V-blades & 4rc.nl

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HomeAircraftHelicopterMain Discussion › rev max limiter
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