slk23

I have a VE and love it, but I would be very careful about buying one.  In addition to all the usual things that can compromise safety, and/or add time and expense, and must be checked carefully (i.e. pre-buy inspection by an expert), there is no comprehensive way to inspect the wing attach fittings.  They can be hiding corrosion, and replacement, while theoretically possible, is so involved that it's not worth the effort.

Also, the only safe way to put a 235 Lycoming on a VE is to remove the starter and flywheel and hand-prop the airplane.  Otherwise the CG will be too far aft, requiring an unacceptable amount of weight in the nose.  Since IO-235 (fuel injected) engines can't be hand-propped, AFAIK, I would expect that the VE in question is overweight.

On 9/10/2021 at 12:39 PM, Kent Ashton said:

See   https://fileinfo.com/extension/heic    Change your phone settings to save them as JPEGs.  I can open your .HEIC pics on my Mac. 

You had a pretty large gap before.  Looks more than 4", but I doubt you are going to gain much with this mod except  "groundspeed"    I am not sure a 1" gap won't make your cooling worse.  I don't think the prop pulls much air through the cowl on the ground and in flight, you might be blocking some of the cowl exit area with the closer prop.  Hard to say without before-and-after-tests so don't take that as gospel. 

If you have a ground-cooling problem, maybe you just need to shut down when there is a delay and restart just before takeoff.  There is no reason to keep the engine idling for  XX minutes when you can just shut it down.  A restart is EZ unless you are hand-proping.  🙂

Follow up:  I'm not sure I gained top speed, but the airplane climbs better now, especially at higher cruise climb speeds.  That makes sense because with lower drag, more power is available for climb.

Ground cooling improved significantly, although the 1" gap between the prop and cowling trailing edge is probably costing me some top end speed (according to Klaus).  After I install in-cowling exhaust, which will help draw cooling air through the cowling, I'll try trimming the TE back another inch or two.

21 hours ago, Ratdog said:

i have been searching high and low and asking on the facebook rutan site as well as here for any concrete info on the rotax 912 being used in a Variez.  There are lots of rumors but no one can even come up with a photo.  Trying to put a rotax into a Varieze would require lots of time and money trying to figure out how to mount it , How to cool it, and the proper prop.  With no flying examples it would not be easy .  It would be an ideal engine probably but the examples i see of it being used as a pusher the engine is not inside a cowl .   So you really dont know what will happen when you mount it backwards inside a cowl as far as CHT etc let alone how many props you would have to go through to find what works the best . 

Stefano Ferretti in Italy used a 912 turbo in his VariEze.  He wrote an article for the Jan. 2022 issue of Canard Aviation magazine (canardowners.com). 

On 10/4/2023 at 4:07 PM, Marc Zeitlin said:

Gary has a Lycoming O-235 on his VE. Probably the most efficient one out there, but it's not a Continental.

Since the VE was originally designed for a Volkswagen engine, it'll fly with an A-75, if its lightweight and if you don't mind degraded performance, particularly in climb. Since very few VEs are lightweight, I certainly wouldn't recommend it.

Wasn't the VW engine only used in the prototype VariEze which was smaller than the redesigned, plans-built version?  Anyway, the VariEze plans do not mention the VW engine AFAIK.  Section IIA covers the  Continental A65, A75, C85, C90, and O-200, and section IIB covers the Lycoming O-235.  In my mind the O-200 and O-235 are by far the best choices.

9 hours ago, Kent Ashton said:

If you can build one, Cozygirrls sell the large gear.  I suppose the worm gear can be acquired somewhere.

It's on their website but that doesn't necessarily mean it's available. 

If you can't fix your electric nose gear then the Long-EZ style manual crank nose gear may be a low budget replacement option.  Someone may have one to sell after installing an electric nose lift system.  You could build one from the Long-EZ plans but I don't think the worm drive components are still available.  The VariEze plans show a pushrod system that isn't recommended.  

I reshaped and extended my cowling and have approx. 1" clearance between prop and cowling trailing edge.  No problems with resonances or any other negative effects.  I was hoping it would help cooling while taxiing and that is indeed much better although I can't say how much of the improvement is due to the reduced prop clearance vs. the new baffle seals.

Pavel, take a look at my cowling some time 😉  KLVK #355

I bought a project with all the major structures and a little of the contouring complete.  IIRC I had a few construction pictures from the original builder.  I did the systems work, installed an engine, made some airframe mods (removed camber from winglets, installed NACA engine inlet, gear leg fairings), finished the contouring, and painted it.  The FSDO inspector had no qualms whatsoever in issuing an airworthiness certificate for the airplane and repairman's certificate for me.  Sample size of 1, but I believe that in general they don't police the 50% rule very stringently unless there are indications that someone is trying to cheat.

If you buy the project take pictures of its current state before you start working on it and more as you progress in the build.  And keep a log (doesn't have to be daily) of your work.

4 minutes ago, Marc Zeitlin said:

So I THINK what you've got is a first edition Section IIA plan set. CP #11 (and the 2nd edition plans) show the fuel system that Stephen posted, and which is the fuel system in every VE out there, including yours, I'm sure. No fuel pump.

Please ensure that you have the latest copies of the plans, POH, and read through all CP's carefully, so that you don't waste other folks' time chasing down information that's easily available.

I've just given Bugstrider access to my copies of the plans.  It's the same Google Drive folder I believe is shared with you too Marc.  

Are those plans pictures from Section II A?  My Section II A is Second Edition and doesn't include anything about a pump.  Looking at the pages you included it appears that Rutan originally used a header tank near the carb?  Second Edition Section II A includes a fuselage header tank (just behind the passenger's head) but no tank on the engine side of the firewall.

3 hours ago, Marc Zeitlin said:

Replace the weatherhead valve, if that's what's installed, with an Allen valve.

The architecture of the system is fine, for a hand-propped, gravity feed system - it's the components that were cheap and crappy.

Oh - replacing the plans fuel sight gauges with Atkinson style clear sight gauges through which one can actually see the fuel level is also pretty much a requirement, if you want to know how much fuel you have left.

Agree with all points.  I'd also recommend an engine monitor with fuel flow/totalizer capability.  I use the monitor as my main fuel management resource and a mirror to periodically double-check fuel levels in the Atkinson sight gauges.

11 hours ago, Bugstrider said:

In addition to the items listed above, are there any additional things that can be done to improve the VE's fuel system design?  I am currently reviewing this section in the plans I have with hopes of understanding the design better and the reason it was designed that way.  In the set of plans I have, I did read a section about adding an electric fuel pump.  I have not finished reviewing this particular section of the plans and still working through them.

Where do the plans refer to adding a fuel pump?

My understanding is that you absolutely should NOT add a fuel pump.  With the main strake tanks teed together a pump can cause an interruption in fuel supply if a fuel cap doesn't seal.  This danger was reported in the COBA (formally CSA) newsletter IIRC.

As I've said, my VariEze's fuel system is per-plans except for the addition of a flow sensor between the selector valve and the gascolator/filter.

I'm not aware of any deficiency in the VariEze's per plans fuel system except the polyurethane fuel hose recommendation.  As discussed previously that should be replaced with something more durable such as high quality automotive rubber fuel hose.  

Turns out I didn't look closely enough at the flight track; I thought it ended away from the airport but it actually he went down while apparently trying to land on Columbia's runway 17.  It doesn't look like he flew a conventional landing pattern, then did a go-around.  Pure conjecture on my part: loss of engine power after the go-around followed by an attempt to glide to the runway and impact into some fairly rough terrain. 

ADS-B track log:
https://flightaware.com/live/flight/N10EZ/history/20220905/1605Z/O22/O22/tracklog

Some very high ground speeds (198 knots) toward the end of the flight.  However, it took around 15 minutes to descend from 15k' to 2.3k' (ground elevation) which suggests it wasn't major structural failure (e.g. wing attach fitting).  Also, there was a climb beginning at 9:41 AM after the long descent (approx. 6 minutes before last ADS-B position) where the groundspeed went down to 106 MPH.  Then another high speed descent (219 MPH) followed by a low ground speed descent into the ground (assuming the ADS-B data is reasonably complete).  Loss of engine power? Deep stall?  Pilot incapacitation? I have no clue.  

More info:
The fuel system is diagrammed in the VariEze plans Section IIA on page 11. 

My fuel system is exactly as pictured on that page except I added a fuel flow sensor in between the fuel selector output and the gascolator.  Also, the Andair gascolator includes a very good filter.  And as Marc said, replace the plastic polyurethane tubing that's specified in the plans with good quality automotive rubber fuel hose.  Regular hose clamps work but I prefer the ones designed for high pressure fuel injection systems because they stay round when tightened.

The fuel selector/value is 3-way: off, both strake tanks, or fuselage header tank. The original Weatherhead valve proved to require a lot of maintenance; the RC Allen valve is much more reliable and worth the money.

BTW the plans do not include a fuel pump; it's a gravity fed system.  In fact there is a danger in using a fuel pump with the wing strake tanks being teed together in case a fuel cap doesn't seal. 

Make sure the fuel tank venting system is per plans and not clogged; it provides some positive pressure.

In my VariEze I have good quality rubber hose (as Marc recommends), some aluminum fuel lines around the fuel flow sensor, fuel injection style hose clamps (which stay almost perfectly round when tightened), an RC Allen fuel valve (05-29500 IIRC), and an Andair gascolator/filter.  On the engine side of the firewall it's all fire-resistant hose.

For the dimensions I would have to take some measurements on the weekend when I'm at the hangar.  But I don't think they are critical.

Here is what Klaus did.

Here's a Long-EZ example that's nice but fairly labor-intensive.

4 hours ago, Bugstrider said:

I've seen some absolutely huge ones on a variety of LongEz's, so I was looking at more designs for the ones on Vari's. 

Klaus Savier (who first put wing fences on an EZ) wrote an article about them.  It must have been in the CSA newsletter?  My memory is his fences were pretty small.

Here is what I did on my VariEze.  In the time since this picture I've replaced them with white plastic.

2 hours ago, thseng said:

Nice.  That gives me a further idea.  The PCB material is sorta translucent...  It would take some experimentation but perhaps you could backlight the text by creating openings in the black solder mask corresponding to the text.  I don't know if the white silk screen print is opaque or not.  The registration with the solder mask might be hit or miss, since this is not the intended application.  

That technique is used and if you do a web search you'll find examples.  Another good place to learn about PCB front panels is the modwiggler website (devoted to DIY synthesizers).

3 hours ago, Upali said:

Looks nice! Hopefully the lettering is durable against frequent use.

I'm putting a few layers of matte clear coat on the panels, especially the switch panel.  So far the most vulnerable area appears to be at the edges; the black paint can chip there.  Hopefully the clear coat will minimize that.

I used a PCB company to make a switch panel and some placards for my airplane. They came out really well for cheap. A fair amount of time learning the software (Fusion 360 and KiCad) and designing on my side but developing new skills is part of the fun 😊

3 hours ago, Jon Matcho said:

I assume you're using this for fill only? Just so others reading this are aware, there are only a few epoxy systems suitable for structural usage. This 635 system is UScomposites.com's own, and there's no information available regarding its mechanicals to compare against the other epoxy systems that are used, and it's an unproven system in terms. @slk23 you may be the first.

All I could find on it is that UScomposites.com does say that it's for structural use (boats, kayaks?) and this MSDS sheet.

Jon,

I was replying to the two posts just preceding mine which discussed fillers. I also specifically referred to using the UScomposites epoxy with micro-balloons. I think the context was clear. 
 

For purposes other than filling/contouring I always use E-Z Poxy. 

In addition to being heavy Bondo also shrinks.  IMHO it's unacceptable except for perhaps pinhole filling.

Recently I've been using the 635 Thin Epoxy Resin System from uscomposites.com.  Combined with micro-balloons it sands like the West Systems epoxy but is much less expensive.

Kent,

Yes, I do sometimes have to idle for quite awhile.  Why you are so skeptical?

This VariEze has a Lycoming O-235.  Weight and balance would not be pretty with a starter, as much as I'd like one.  But I've come to appreciate hand-propping because I am immediately made aware of leaking valves, etc.  It's also satisfying to develop the skills involved. 

More pix to follow.