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Harley O. (Pete) Britton

Member
I have a couple quick questions about Van's rear throttle kit. First, is Van's kit compatible with the deluxe throttle mounted up front or does it have to be custom fitted or modified? And second, I have the printed plans for the rear throttle and wonder if the supplied templates for cutting the bulkhead holes for the push/pull rod are really accurate? Normally, I would assume the templates show the exact location for the holes but on the prints they are labeled "theoretical" pushrod hole. In addition, the written instructions say to use the templates as a starting point for the locations. They go on to say to drill a 3/16 or 1/4 hole on the upper crosshair from each template. I see no crosshairs anywhere on the templates and the depicted holes are oblong in shape like you would expect them to be. I can call Van's on Monday but I often get more helpful info from this forum.

Thanks,

Pete Britton, RV-8 Slow-Build Fuselage Kit
 
Rear throttle install and frustrations

Hi,

The rear throttle kit goes in fine, and the connection to the deluxe fwd quadrant works fine - the connection is a long pushrod that gets fed through a few bulkheads, including the important F-804 box.

I found that the template guides on the plans for the pushrod cut outs were fairly close, made a good starting point, **BUT** on my fuselage, I also used the manual trim, and the holes and routing location for the manual trim cable conflicted severely with the pushrod for the rear throttle. Mine was the non-matched hole fuselage. I complained bitterly to Van's about this, because I ended up having to reroute the manual trim cable that was already installed, including punching more holes in the F-804 bulkhead box about an inch below the first ones. Because the pushrod holes intersected the already drilled manual trim cable holes, the result was a rather large cut-out in the F-804, so I made some doubler plates to close off the abandoned trim cable holes and reinforce the area. I was not a happy camper!

From a quick glance at a friend's newer RV-8, I have the impression that the -1 matched-hole kits have the trim cable routing changed to avoid this conflict, but I'm not certain.

So, if you have electric elevator trim, no worries, the rear throttle kit goes right in. If you have the matched-hole -1 fuselage kit, I think you are OK with manual trim and rear throttle, but be careful. If you have the older fuselage, then benefit from my experience and route the trim cable an 1" or more lower than they show on the plans to avoid conflict with the throttle pushrod.
 
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rear throttle install

Hello Harley,

I installed a modified version of rear throttle kit to the front deluxe kit: I installed two levers in rear: one for throttle and one for prop. I was asking for trouble and got it. Was not happy with my (excessively large) holes. Ended up putting substantial doublers on both F804 bulkheads and replacing the F805 bulkhead. Because of my mod, the plans were of limited use to me.

In retrospect, I should have built myself a type of gauge, made of wood, basically a ruler the length of the interconnect rod with five legs (like an E, but with five legs instead of three), the end legs being the length required to reach the attachment point at each throttle quadrant and the middle legs being the correct length to line up in a straight line with those end legs. These middle legs are positioned along the "ruler" part so that they correspond with the bulkhead positions. This will give you the correct place to center your hole at each bulkhead.

BTW, the oval shape of each hole is necessary: there is some vertical movement as the levers are moved fore and aft. It took me quite few install/remove/file away/reinstall of the rod and quadrants to get the holes just large enough so that no rubbing takes place. In this aspect the size on the plans is about correct.

Hope I'm being clear and that this helps.

regards,

Normand RV8 Finishing
 
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