DX7 Setup Sheet

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jimxx
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DX7 Setup Sheet

by jimxx » Mon May 05, 2008 6:53 pm

Found this (Microsoft Word) DX7 setup recording sheet. Much more usable than the generally useless one on the Spektrum website.

Filled in a beginner setup for my nearly complete Mini T that I think satisfies the manual. Would appreciate comments.

Biggest area of earth shaking controversy will be the lack of expo on the cyclic. If you think this is really important for a beginner, what percent would you suggest? Don't know how important expo is on the rudder, being gyro controlled and all. The swash expo is a totally different thing I think, and is intended only to linearize the swash plate movement. Leaving it off for now.

Seems to be (or maybe it's old postings) that there is some problem with Spektrum-type rc gear in Europe. Is it in wide-spread use now?

Jim
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Pippin
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by Pippin » Mon May 05, 2008 6:59 pm

There is Expo for the cyclic. If you program in Expo on the elevator and the aileron. You don't really want Expo running on the pitch curves as well, thats why they are done in this way.

Phil
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jimxx
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DX7 Setup Sheet

by jimxx » Mon May 05, 2008 7:01 pm

Sorry, I don't know how to attach a .doc file to my posting.

Jim

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scooter
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by scooter » Tue May 06, 2008 4:51 am

I setup all my helis for 7.5deg cylic pitch and to have fast cyclic response for doing a flip/roll.

But i also have 25% expo on the ail/elev to still make it easy to hover and fly nice circuits.

I also use 15% expo on the rudder as this also helps during circuits and flips.
I did experiement and found the above to work well

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by mactabak » Tue May 06, 2008 3:13 pm

Jim, I dont use an expo, I found it can cause more problems than it solves! It makes the heli feel stodgey or spongey around the centre stick position in my book. If your flying a titan like me, you really dont need it.

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scooter
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by scooter » Tue May 06, 2008 9:29 pm

Put some green paddles on, 7.5deg cyclic and arms on the outside :) you'll be using expo then. Expo allow you to have the best of both worlds, soft in centre and very fast at extremes if need be.
Most people do use it from what i here.

jimxx
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DX7 Setup Sheet

by jimxx » Tue May 06, 2008 10:38 pm

What do you mean, 7.5 degree cyclic? I thought I was understanding pitch curves, throttle curves, dual rates, expo, etc. pretty well. But I'm not registering the 7.5 deg cyclic.

Maybe I'm just having a mental blank period.

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by mactabak » Tue May 06, 2008 10:44 pm

7.5 deg cyclic is how many degrees the swash tilts.

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scooter
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by scooter » Tue May 06, 2008 10:45 pm

Thats when you move the stick to mid way so theres 0 pitch then if checking aileron have the rotors in line with the boom, move the aileron and hold then check with pitch guage. Turns the rotors 90 deg and then meas elev
You can then make your ail and ele respond the same in flight and also any more tha 8 deg will ussually result in binding and/or bogging in flight if not experienced.

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scooter
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by scooter » Tue May 06, 2008 10:47 pm

mactabak wrote:7.5 deg cyclic is how many degrees the swash tilts.

Ross


Your not measuring the swash angle. I think it would be different due to the arms and the ratio on the head.

jimxx
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DX7 Setup Sheet

by jimxx » Wed May 07, 2008 12:19 am

I'm really answering this too quickly, maybe not giving it enough thought.

I see two ways to change the swash plate tilt. One is with the Dual Rate function and the other is with the Swash Mix.

Now the Swash Mix is +60, +60 and -60 which is giving me the assembly manual recommended + and - 10 degrees full collective (In a setup mode, not flying mode). So I guess the Dual Rate is the only adjustment possible. I arbitrarily set it to 80% on Aileron and Elevator to make it more a beginner setup , but I never thought to measure the resulting tilt in degrees.

What swash plate tilt (in degrees) would be expected on a Mini Titan with 100% on the Dual Rates at full stick deflection?
Or if we are talking about the blade angle of attack as opposed to swash plate tilt, what range would you expect to see 100% Dual Rate in full travel?

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scooter
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by scooter » Wed May 07, 2008 12:28 am

Do not be mistaken we are not talking about the tilt angle of the swash, due to the ratio on the arms etc 7 deg on the swash will be very diffent on both the flybar and main rotors.

You will find on 120CCPM that in the swash mix menu 60 on the ail and 60 on the elev will not in fact give you the same cyclic pitch on the rotors due to the geometry of it all, yesterday a figure of 60 on both gave 8deg on one and 10 deg pitch on the other (trex500 i was setting up). I used 50 and 60 as the final setting for 7 deg cyclic pitch.
It is often overlooked when setting up, cyclic pitch is important and will give you a more uniform feel when using ail and elevator so you don't have to compesate for the reaction of it as each would be different.
The last figure in the swash menu (pitch i think) sets the overall pitch range, the other two figures are for setting cyclic pitch and should be ustilised.
The purpose of dual rates it to be able to change settings with either flight modes or switches. But again i use expo so that you can still have it hovering easy for beginner but when you want to really get it to flip/roll it will do so very fast.
You should set up you cylic pitch in the swash mix menu.
Then use your dual rate or expo. I believe expo is better as if you get in trouble you can still recover much easier.

jimxx
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DX7 Setup Sheet

by jimxx » Wed May 07, 2008 1:07 am

Thanks, Scooter. I'm getting the idea now. For instance, I hadn't separated in my mind the Swash Mix Aileron and Elevator effect from the Pitch effect. I just knew it seemed to work out OK with the default 60 numbers as far as the range of the collective was concerned.

I've done a really great deal of Internet work on RC helicopters in the last month - this discussion is the first I've seen on cyclic pitch range values. Rather surprising. Is a very logical thing to think about it seems to me, even if it doesn't concern crash/don't crash as much as the more frequently covered topics.

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scooter
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by scooter » Wed May 07, 2008 1:15 am

Most people just increase the value to maximum before it binds or are not aware.

I rather a consistent model. For instance I have 3 helis and if i had 60 as the value on all 3 swash settings for all three helis they would all behave radically different.
At least this was not only is each heli more consistent, also each models individual aileron and elevator inputs respond the same as the cyclic pitch is the same.

I too was only aware of this after about 6 months of flying!

Has it helped? Yes it has and i know that the heli will not bind and also when doing a flip if i give it a good dose of collective the blades will not bog like mad and want to stall. Theres no need to max out all the settings.

Remember expo is your friend. If you learning a new trick it also helps so that you do not introduce unwanted actions while performing the trick. The last thing you want it the tail to spin when doing a flip! My control is good but not that good!
Also it helps in FFF as well, to be able to fly smoother.

jimxx
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DX7 Setup Sheet

by jimxx » Wed May 07, 2008 12:52 pm

Hey, Scooter,
I find that with collective set for 0 pitch, D/R at 100%, Swash Mix at 60, 60, -60, flybar level, that the aileron and elevator max stick deflections do indeed come out to about 7.5 degree blade angle of attack. Don't see any interaction between aileron and elevator, which is good I guess.

But, moving to max collective with max aileron or elevator, however, gives really high angles of attact, maybe about 18 or more degrees. What would be the significance of this in advanced flying including autorotation? Seems you would need to be careful in autorotation to not give too much cyclic in the flare or could stall a blade.

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scooter
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by scooter » Wed May 07, 2008 8:25 pm

Yeh 18 deg is about right.
In an auto by the time your using full pitch (to stall the blades and flare) you wouldn't be unputting full cyclic.
Give it a go and experiement

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