What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Rear seat throttle - any info?

Mark Albery

Mark Albery

Well Known Member
Just got to the bottom of page 8-18 of the -1 fuselage and it makes reference to provisions for the rear seat throttle option.

This raised a bit of an alarm bell, as I haven't seen any reference elsewhere to it as an option, so I sort-of assumed that it was standard.

Re-checking the order form, there isn't any reference to it and nothing in the on-line catalogue. Running a search only pulls up drawing OP-2 at $3.

So - how can I order a kit?

Can I ignore it for now and easily retro-fit it later?

Thanks,

Mark Albery
(RV-4 G-MARX and RV-8 standard kit in progress)
 
I liked Paul's "throttle stick" so well I decided to install a permament version. Simple, very light, and unlike the Van's kit throttle, passengers won't be bumping it and making the PIC nervous when the engine changes tone.

 
I like it!

I like your solution Dan - might not even be very hard to implement as a retrofit - I'll have to think about it some rainy weekend...

Paul
 
Paul,
1/4" aluminun tube tapped 10-32 in the ends. I machined a knob for the back, 3/16 bore and countersink for a #10 screw, then counterbored 1/4" bore halfway through for the rod. The front end is just a pin eye stolen from a turnbuckle. The slides are a 5/16 snap bushing at the front and a nylon/aluminum sandwich at the rear. A snap bushing doesn't work well at the back because the bulkhead is slanted.
 
It looks like you could use the hardware from a RV-8 or 8A rear seat rudder pedal kit to do this if you did not want to do the machining. Maybe you could buy just a few parts from Vans. The knob looks just about like the rounded end of the rudder push tube. You might need a longer tube though.
 
Dan,

Your "knob" looks like a SafeAir1 Static vent.
SP_03.jpg

And they come pre-threaded.
 
Mark,

I have an RV-8 rear seat throttle kit available if you would like it, 20 quid plus what ever it oosts to post. Email me on peter 'at' sportingaero dot com with an address if you would like it.

Pete
 
Adam Oke said:
The link you provided states the RV-8 rear quadrant is throttle only. Can you get 3 levers for the rear seat?
Click to expand...

Adam,

There's not a lot of room against the left sidewall in the rear seat. It would be a tough engineering challenge, in my opinion, to fit all three levers in the back seat without seriously compromising the backseater's left leg-room.

That's why Van's RV-8 rear quadrant sub-kit includes only a throttle.

Not that it couldn't be done, of course. Just pointing out the reason that Van hasn't done it.
 
Very nice

DanH said:
I liked Paul's "throttle stick" so well I decided to install a permament version. Simple, very light, and unlike the Van's kit throttle, passengers won't be bumping it and making the PIC nervous when the engine changes tone.

Click to expand...

The other nice thing about this setup is that it doesn't interfere with the manual trim cable (if you have one). I installed the Vans rear seat throttle very early in the project. Near the end when I installed the manual trim cable, I realized that the two don't go very well together. Consequently, I had to remove the stock rear seat throttle.
 
That being said, has anyone fabricated the 3 lever quadrant into the rear seat? Any pictures out there at all? Ideally I would like to be able to take passengers in the front and still have throttle, prop, and mixture for personal comfort.
 
Back seat

Adam Oke said:
That being said, has anyone fabricated the 3 lever quadrant into the rear seat? Any pictures out there at all? Ideally I would like to be able to take passengers in the front and still have throttle, prop, and mixture for personal comfort.
Click to expand...

A couple of additional issues that you are going to have to work out. Getting brakes in the back is going to make the throttle/mixture/prop control look simple. But the biggie is that most people in the back can't see all of the instrument panel. The back seat is lower due to the profile of the canopy. But, as we say in aviation, anything is possible, given enough time and money. :rolleyes:

John Clark
RV8 N18U "Sunshine"
KSBA
 
Last edited:
Adam Oke said:
That being said, has anyone fabricated the 3 lever quadrant into the rear seat? Any pictures out there at all? Ideally I would like to be able to take passengers in the front and still have throttle, prop, and mixture for personal comfort.
Click to expand...

Adam,
Gert Van Der Sanden fabricated his own 2 lever rear controls. The link I originally provided is now dead. Contact me via email [left click on my user name to access my email address] and I'll send you a PDF file with photos and explanations from Gert.

Another alternative would be to use the vernier/cable style controls used on the side by side RVs to fabricate 2 or 3 controls for the rear. These could be mounted vertically on the F-806 bulkhead.
Charlie Kuss
 
Last edited:
But why???

Why on earth would you want passengers in the front of an RV8? What's wrong with the back?:confused:

I've flown in the back of an RV8. I'm 6'2", the pilot was I guess around 5'8". I could barely see the instruments and I certainly couldn't have landed it with any safety. Also no brakes and no flaps. As for all three levers, well its hard enough already to keep from nudging the throttle with your left knee already - in fact I managed to close it near the top of a stall turn. Not at all what I intended or wanted.

I guess nearly everything could be fixed given time, money and ingenuity, but because of the shape of the canopy, and consequently the low rear seat, I think there is no way to fix the view.

Although I have a rear seat throttle in my RV8, in retrospect I'm not sure how useful it will be. The next one (!) won't have one. I have absolutely no intention of flying passengers in the front seat.

Chris
 
Hey Chris,

Why not? I've flown passengers from the right seat, I've flown them from the back seat... actually hundreds upon hundreds for flights from the back seat when flying gliders. I have flown gliders where the only panel is in the front and you have to peer around the passengers shoulder. I have no issue with it and enjoy the different perspective and challenge.

I thoroughly enjoy flying passengers. If the pax is licensed or not it’s always fantastic and I like to give them the best experience possible. Putting the passenger up front where there is no fat head in the way, all the bells and whistles to be mezmorized from, and the view is much better. When I took my first introductory flight, that's what made it all that much better!

Having said that none of which have been in an RV. I would like to have a seat in the back with someone up front and see what the perspective is like and how realistic the idea is. Who's flown passengers from the back seat? Realistically how restricted is your view ... I mean, moving your head to one side is not an issue for me. But if it's unrealistic due to seating too low then someone enlighten me.
 
Last edited:
Hi Adam,

I agree that its great to give passengers a great view, but my single trip in the back of an RV8 suggests to me it's not the place to be P1. I flew some loops and stall turns from the back but those manoeuvres involve a lot of looking sideways to see that the wings are level during the pull up. Barrel rolls and aileron rolls were OK too as you can see the horizon out the side so you can judge when you are S and L. But although I craned my neck hard to get a view out the front I just couldn't see enough to have had a sensible shot at landing it, despite being I guess around 6" taller than the guy in front. (He reads this forum too, so Andy, if I'm wrong, apologies <G>, - but would you fly P1 from the back??)

I thought some numbers would be helpful, so after a quick trip outside to get some measurements I have the following:

The roll bar is 39" above the cockpit floor, and the glare shield is 9 1/2 " below the roll bar, around 29 1/2" above the cockpit floor. So my eye height is only 2 1/2 above the glareshield.

I'm 74" tall, crown to rump length is about 38" (short little legs), and my eyes are about 6 " below the crown of my head, so rump to eye level is 32 inches if I sit up straight.

The cushion will only add an inch or so, especially once compressed, so that would make my eyes 3 1/2 inches above the glareshield. Sitting in the rear seat, albeit without a cushion, I can't see the spinner, because of the way the nose slopes downwards.

I tried to get some measurements off the canopy but the best I can come up with is that I estimate the canopy over the back seat is about 6" lower than over the front seat.

So overall, yes, I think the rear seat is too low. On the other hand, I can say that the view out of top of the bubble when upside down is spectacular.

To return to Mark's original question about a rear seat throttle, I think now, having installed one, I should have asked - why? What's it going to get used for? If you fly from A to B you don't need to alter the settings. If you fly "casual" aeros you (mostly ) don't need to alter the settings. Pilot incapacitation? But realistically, what else? Just another one of those decisions that in retrospect I think I got wrong.

Just my two pennies worth.

Chris
 
interference between manual trim cable and rear throttle

Geoff said:
The other nice thing about this setup is that it doesn't interfere with the manual trim cable (if you have one). I installed the Vans rear seat throttle very early in the project. Near the end when I installed the manual trim cable, I realized that the two don't go very well together. Consequently, I had to remove the stock rear seat throttle.
Click to expand...

Hi Geoff,
I ran into the same thing on my QB. The hole locations specified in F804 for the manual trim and the rear throttle pushrod overlap. I ended up drilling another set of holes through the F804's an inch lower for the manual trim cable, and I made a set of doublers inside the F804s to reinforce, since the original holes overlapped to form a big hole.

I complained fiercely to Van's - it would be so easy to just update the plans to warn the builder of the conflict and to just drill the trim cable holes an inch lower. They were not very interested in doing anything about it. It turns out that they fixed this in the new prepunch fuselages, so its not a problem on the new ones. So, someone else must have complained too. I have one of the last standard-kits to come back as a QB (months after the prepunch kits were shipping for slow-builds).

Steve
RV-8QB FWF
 
The rear quadrant kit is there too

chaskuss said:
This link is for the FRONT seat controls, not the rear seat. The info for the Vans rear seat throttle is shown on an optional drawing that comes with the kit [ Dwg OP-2]
Charlie Kuss
Click to expand...

The rear quadrant kit is listed at this link as the last item - scroll down a bit.

Steve
RV-8QB FWF
 
Chris...
I think now, having installed one, I should have asked - why? What's it going to get used for?
Click to expand...
Unless your aircraft has full dual controls in the rear seat (stick, rudder and throttle and PTT) you cannot be taught formation in that aircraft... so there's your reason :D Or are you now chickening out of learning this :(

Adam...
...and the view is much better
Click to expand...
The usual comment from the RV-8 Rear seat is "what a fantastic view"... It's more comfortable back there, there's more room, and as above, the "standard" rear seat controls give a more than ample experience ;) The view is only limited on the ground... In addition, airborne, being behind the wing gives a better view of the ground.

I've now got ~80hours in the RV, varying from sitting in the back during the test flying, formation flying (up to formation aeros) from front and rear, including instructing, aerobatics from both seats, again including instructing. Flying from the back is not a real issue except:
  1. The lack of "extra" controls / switches. As you've been proposing, but very difficult to get many of them back there.
  2. The limited instrumentation. You can see the top ~4" and the side 6" of the main panel OK, and the side panels fine. The lower / centre of the main panel you will never see. We ensured, and it works (does it not Chris?), that Main ASI, Alt, 'g' and Sby Engine Insts can be seen / flown to from the rear. Dynon hard to see (top centre), GPS (bottom centre) impossible.
  3. Landing... I am still a low time taildragger pilot... I reckon I could land it from the rear, but only in extremis / emergency. Taxiing would be difficult! That said, I am not sure if it is any worse than a warbird type aircraft for view!
My personal view is trying to equip an RV-8 to P1 from the rear seat, with a non-pilot in the front, is an interesting project, where the time and effort required far outweighs the (small) benefits :eek:

The "main" benefit does not seem to have been mentioned - that of limiting the CG movement between dual and solo. This does need to be considered during the build and wherever you end up will be a compromise. If your flying were to involve lots of aerobatics, maybe including formation aerobatics, and you needed to fly both dual and solo, then a rear seat P1 (like an Extra) would be of benefit. The stock RV-8 is hard work solo on stick forces, and needs care with a heavy pax in the rear v the Aft CG limits.
 
Defintely NOT chickening out!

Ah - I didn't know that for formation the the instructor needed a throttle tho of course it makes sense - I've only done formation in Bulldogs and Grobs, where of course there are full dual controls tho so far the instructors haven't needed the throttle...

As you say Andy, it is possible to see altimeter, ASI, accelerometer and s/by engine instruments.

No access of course to radio, transponder, flaps. All doable I'm sure but a huge amount of effort and probably duplication of kit.

Chris

Cutting perspex. I love it.
 
I've just finished off the rear seat throttle now with the linkage to the main quadrant. The only real snag was re-routing the manual trim cable which wanted to occupy the same space as the linkage rod. My routing now goes just below both quadrants before sloping up from 806 to 807 bulkheads and then following the longeron.

My motive for the back seat throttle and rudder was also considering the possibility of aero and formation coaching from my current fairly basic level.

I've been in touch with Paul Winters lately, who is a bit further on with his -8, having just got his canopy rivetted down.
He had a similar observation to Andy re. visibility of instruments from the rear, but also tried a reasonably large occupant in the front, observed that the LHS of the panel can get partly blocked by a hand on the throttle raising the arm just enough to get in the way. I'll probably be investigating a basic 2.25" instrument stack down the RHS of the main panel - still a little way off.

Paul sent me a few nice pics and notes for the canopy fitting; I'll forward them on to you, Chris, if I can find your e-mail.

p.s. I screwed up my first go at the canopy slider delrin block, you don't have much edge distance left if you adhere to the spike-to-track 1/8" clearance.
 
Rear Seat Instrument view

I'm 6' 4" tall. When flying from the rear of my friend's RV8, I find I can see about 2/3rd of the instruments. However, I have to tilt my head to see some of them. This sometimes causes me to enter a shallow bank inadvertently.
I've watched all the discussions regarding rear seat instrumentation. For my 8A project, I think I'll just install a "lipstick" camera aimed at the center of the panel. Mount a TV screen on the rear of the pilot's seat and the issue is solved, simply, cheaply and at minimum weight.
Charlie Kuss
 
Has anyone thought about pilot incapacitation? No controls of any kind in the back. Sounds like a reach around, would be tough.

Power, stick and rudder would get the aircraft on the ground. Not having any and it might get ugly.

I put em in my 8 fastback!
 
You must log in or register to reply here.
Back
Top