VP-X and RV-10

[douglassmt]

For those of you with RV-10s and the VP-X unit, how are you (or are you?) using the flap overspeed feature to allow moving the flaps from reflex to zero position at any speed, but preventing movement of flaps below zero position at speeds above Vfe? I thought I understood that the VP-X would allow this when I bought it, but it appears I heard wrong. If I can't do it, I'll probably just disable the flap overspeed feature. Inquiring minds....

Nothing turned up in a search of the forums

 

[Bill.Peyton]

Bryan,
The VPX does allow you to do what you have described. It is on Page 57 of the manual. You can set the overspeed condition to occur at any point of the travel. Just set the overspeed at anything BELOW the 0 degree position and you will be all set. This will allow you to go between reflex and 0 at any speed, but not below the 0 position until under the speed you set when you program the box.
Bill

 

[douglassmt]

???

That's what I thought, but it isn't working for me and Marc Ausman doesn't know anything about it. Are you doing it?

The VPX certainly allows you to do the reflex (pg 57) but what I'm seeing and what Marc says is that the overspeed function will not allow you to move the flaps down from any position over the max speed you put in. It would be really elegant if it would work but if it doesn't I'll just turn off the flap overspeed function.

 

[Bill.Peyton]

Since I haven't flown I have no idea how to tell if it is really working. That's the way I set it up. The book says it should work, but I think what you are saying is that when you turn on the overspend feature it disables any flap movement at all over the speed u set. Are u sure that u have the position programmed I the VPN correctly?

 

[douglassmt]

Pretty sure

Yes. I've been thru it several times. My up limit is about 216, zero is at 198, 1/2 is at 81, full is at zero. I set my overspeed ias at 90 kias, and the overspeed set point at 195, 190, and 180. I can't lower flaps from reflex until my ias is below 90 at any of these settings. When I asked Marc he said they don't offer that function. I had this discussion with someone at VPX before I bought it and thought I heard that it would work, but there must have been a disconnect.

Is anyone out there flying a -10 with a VPX and figured this out?

Btw, Marc's been great, very helpful, and I still love the product, no regrets.

 

[Bill.Peyton]

I think I know what is wrong with your setup. Try reversing the outside leads of the flap position potentiometer. By doing this the resistance will go up as you add flaps. The VPX software wants to see a lower value for less flaps (0 deg.) and a higher value for more flaps (ie 40 deg.). What I believe is happening is no matter where you put the set point, you always exceed the threshold. In your example, if you reverse the outside connections, you should see 0 in the reflex, 18 at neutral, 117 at 1/2, etc.
I am only guessing, but I think that what has happened is that, in software, the motor leads need to be polarized in sync with the potentiometer feedback loop. The VPX allows you to reverse either in the config setup. The simple way to make this change is at the connector of the VPX. Just extract the relevant two pins. PM me with your phone number if you want to discuss more....

Edit. I just re-read the paragraphs pertaining to the flaps. Here they are:

"Max Flap Speed
The IAS above which the flap down switch is disabled and the flap over speed
alarm is triggered. Set this value to 0 to disable both the flap down switch
disable function and the flap over speed alarm.
Over speed Position
The flap position below which the flap over speed alarm is triggered. If the flaps
are BELOW this setting and the IAS is higher than the Max Flap Speed, the Flap
Over speed alarm is activated. Since each aircraft is different, this speed may
correspond to 10° of flaps, or maybe 30°. We recommend you set it somewhere
just a bit BELOW the flap up setting. When we say BELOW we mean the actual
physical flap position, not the numerical value used to show the position. Here
are some examples:"

What this is saying is exactly what you are seeing. It is only the alarm that you can program for a specific position (and all those below). The switch is totally disabled at the airspeed you have as your set point. This sucks if it is true. I am going to call Marc and see if this can be changed with a software upgrade.

 

[douglassmt]

Not sure

Bill -

I'm not sure you are right about the potentiometer. Reading the manual, he says several times that your potentiometer may have higher "values" at either end of the flap position and that the VPX can handle either way. There are even dual diagrams showing the positions both ways. I could be wrong, though.

It sure does seem like an easy fix that would make the VPX even more elegant for the no-Vfe range of flap operation in the RV-10.

Let me know what you hear.

 

[MCA]

The position can be either high or low at each end. You simply set the the flap up limit and the down limit to the corresponding high or low value (and trim too). The system then figures everything out from there.

Sorry, I had to cringe when you said you re-wired it instead of just changing the limits in the setup menu.

We can add a software switch for:
- ignore VFE limits on top position
- raise flaps to first stop (rather than top) when you press the flap up switch

In the interim, it is not critical that you differentiate between reflex and trail positions while entering or leaving the pattern. The reflex position give you 2 kts of speed (in cruise) and reduces stall by 2 kts when in trail (according to Van's).

So as long as you are in reflex in cruise and flaps half or down to land you're ok. It might be nice to put the flaps to trail while coming into the pattern fast, but not necessary, as far as I can tell anyway.

 

[douglassmt]

Reflex

Marc -

I'm by no means an expert, but I was taught (and my early flight experience seems to confirm) that going from zero to reflex gets you about 10 knots in cruise. Mike Seager teaches to drop flaps from reflex to zero (with no Vfe) to help slow down while approaching the pattern. It's surprising how much it does to slow you down. Other owners can weigh in if I'm way off.

I'm not sure I'd want the default stop position to be zero instead of reflex (as it is now), I'll have to think about that. Maybe experienced RV-10ers can weigh in.

If you make these choices optional in the configurator, then everyone would be happy I guess. Thanks for your attention to this. I'm VERY happy with the VP-X and enjoy bragging about it to the certificated plane owners that stop by - and watching their jaws drop!

 

[Bill.Peyton]

Marc,
It would be great to incorporate the software patch to allow us to move to neutral above VNE. Although I am not flying, when people stop in to see the progress the question is always,m "what's that big red box for?" Two hours later they are amazed!
Bill