[Pmerems]

Gents,

Gents,

As I mentioned in my initial post (http://www.vansairforce.com/community/showthread.php?t=34773&highlight=pcu) that there is a problem with the latest bracket (VA-153PC) and the PCU5000.

I spent many hours trying to figure out a solution that was acceptable to me. I made a few similar brackets to the VA-153 that fit the PCU5000 properly but still had several issues with respect to installing the bolt and still have acceptable clearance during the arm rotation. I wasn't satisfied with the results.

I looked on the web for photos of the VA-183 to see how it was installed. I called Van's to see if they had any old stock of the VA-183 but they didn't. I was told the reason Van's stopped selling the VA-183 was because builders had issue with the bracket interfering with the oil hose coming off the rear of the accessory case. Several photos on the web show this interference and many builders cut away some of the bracket to reduce this. However cutting away the bracket also reduces the strength and rigidity.

So I decided to design my own bracket that captured the best of the VA-183 (mounted to the base of the governor and no control arm bolt installation issue ) and the VA-153 (alignment to the forward side of the control arm-allows a generous control cable radius from the firewall and keeps clear of the oil hose).

After several iterations I am proud to say I accomplished my goal, a bracket that works great with the PCU5000.

The bracket is made from 4130 steel (.063) with all cuts and bends were made with simple hand tools and a vise.

You can download the prototype engineering drawing at www.experimentalaero.com/Drawings/EA-PGB-PCU5000_Rev-.pdf. I recommend making a quick prototype out of scrap aluminum for a fit checking.

Keep in mind that I have not flown with this bracket yet but hopefully by years end I will. Please provide any feedback. I hope this helps other builders.

 

[algrajek]

You are not making these, by chance, Are you?
AL Grajek

 

[Bob Kuykendall]

A minor tweak...

That looks like a pretty neat product!

One improvement I'd be inclined to suggest is to have a welder weld in a wedge of steel to bridge the gap in the stiffening flange like so:

I think you'd find that that stiffens the part a lot and makes the prop control feel crisper. It might also extend the fatigue life of the part, but it's hard to tell with these things.

Thanks, Bob K.
www.hpaircraft.com

 

[ao.frog]

I need one too

Looks good!

I haven't received the engine, the 5000 and FF-kit yet, but it seems like I'll be neeeding one too.

If you decide to make the, sign me up for one please.

 

[mcencula]

That looks like a pretty neat product!

One improvement I'd be inclined to suggest is to have a welder weld in a wedge of steel to bridge the gap in the stiffening flange like so:

I think you'd find that that stiffens the part a lot and makes the prop control feel crisper. It might also extend the fatigue life of the part, but it's hard to tell with these things.

Thanks, Bob K.
www.hpaircraft.com

I came to the same conclusion. Besides feeling crisper, I would expect a crack to form at that bend over time if the flange isn't continuous.

Otherwise it looks nice. Thanks for sharing the drawing.

 

[Pmerems]

Bracket

Gents,

Sorry I haven't started making them. They aren't too hard to manufacture in you garage shop. Some 0.063 4130 sheet (ACS), a saber saw (or hacksaw), Drill press, files and some hardwood blocks are all you need. Should take about 1 hour or so.

One suggestion made was to weld up the area noted in red to make it more rigid. I actually made one this way but was concerned about how stiff it was. I actually prefer the slight flex in the one without the weld. Van's VA-183 was bent in a similar way and not welded. I haven't heard of any cracks or failures of this design.

For those who decide to make the bracket please let me know how it turns out.