[JHines]

Can anyone point me to photo of a T/U canopy without the gas struts? What did the hold-open device look like? Was it like a manual "hood prop" on a car?

 

[N941WR]

Jonathan,

Why do you not wish to use the struts?

If you are worried about jettison the canopy with the struts; rest assured, if you pop that canopy in flight, the struts will pull right out.

 

[Mel]

Just another opinion! $.02 Please.

I would never put the struts on a TU canopy. They are in the way when entering or exiting the cockpit. (Maybe it's just my big feet!). I also don't share Bill's belief that they will tear away at jettison time. They may come loose, but what kind of "flailing" will they do in the process. I have removed many of the struts for customers that do extensive acro.
The original RV-6 canopy prop-rod is a short one similar to an automotive hood prop, attached to the top of the left panel support rib. On my airplane, I added a longer one to the passenger side, because the original canopy didn't have the stiffener that the later models have. Both of these (BTW) are completely disconnected with the canopy closed.

 

[N941WR]

...I also don't share Bill's belief that they will tear away at jettison time. They may come loose, but what kind of "flailing" will they do in the process...

Mel,

I would like to test this some time. Do you know of anyone with a bad tip-up? I'm thinking we could test this on the back of a pickup and see what happens and at what speed.

I've seen a few convertible tops rip off and take bolted on cross bows with them at a lot less than than 100 MPH. Thus my feeling that the rods would just pull right out.

 

[Mel]

Bill,
I don't know of one, but I agree this would be a good test to do.
I don't doubt that the struts would rip out. My concern is how they would affect the trajectory of the canopy.
On a convertible top, everything is attached at the rear of the passenger compartment away from the "cockpit." The struts on the canopy are attached forward of the passengers.
Anyone want to volunteer a built-up canopy for the test?

 

[jsharkey]

Will the curved hinges "un hook" from under the fwd skin on an emergency release? The original canopies had simple lugs and a notched fwd skin. (They leaked bad I guess).

Has anyone successfully released one of the newer curved hinge canopies in flight?

Might be a myth busters back of a pickup test after all.

Jim Sharkey
RV6 Tip-up

 

[JHines]

Thanks for the info.

I don't even have the tail kit yet, so the canopy is a long way off.

I already know I want some heavy options (C/S prop, full IFR panel, "golf club" shelf). I aready know I should "build light".

I am just trying to think of every possible item to leave off to save weight and speed up the build. E.g., no primer, no blind rivet phobia, maybe no gas struts. I'm sorely tempted to use an O-235 if it can run auto fuel.

I intend to leave off the standard jettison mechanism completely, perhaps replacing the canopy pivot bolts with some pins for maintenance purposes.

I'm not worried about bailing out. I didn't wear a chute when I had a spam can, so bailing out wasn't an option. I won't be doing any aerobatics, so I figure as long as I can keep the fire hazard to equal or less than a spam can, I'm no worse off. I'll put a canopy knife or similar in the cockpit in case I flip it over on the ground.

 

[Sam Buchanan]

Thanks for the info.

I don't even have the tail kit yet, so the canopy is a long way off.

I already know I want some heavy options (C/S prop, full IFR panel, "golf club" shelf). I aready know I should "build light".

I am just trying to think of every possible item to leave off to save weight and speed up the build. E.g., no primer, no blind rivet phobia, maybe no gas struts. I'm sorely tempted to use an O-235 if it can run auto fuel.

I intend to leave off the standard jettison mechanism completely, perhaps replacing the canopy pivot bolts with some pins for maintenance purposes.

I'm not worried about bailing out. I didn't wear a chute when I had a spam can, so bailing out wasn't an option. I won't be doing any aerobatics, so I figure as long as I can keep the fire hazard to equal or less than a spam can, I'm no worse off. I'll put a canopy knife or similar in the cockpit in case I flip it over on the ground.

Jonathan, I know Mel has strong feelings about the tip-up struts, but he is definitely in the minority on this issue.

You will gladly trade the extra few ounces for the convenience of the struts. I have no doubt many hundreds of tip up owners would agree. I don't think Vans would have included the struts if they didn't consider them an upgrade from the old prop rod.

Your choice......you will enjoy the tip up canopy either way.

 

[Mel]

The hinges will NOT unhook from under the skin.

Will the curved hinges "un hook" from under the fwd skin on an emergency release? The original canopies had simple lugs and a notched fwd skin. (They leaked bad I guess).

For the canopy jettison feature, the skins must be notched. Mine have been notched (notches covered with tape similar to what glider pilots use to cover wing root joints) for 15 years. Never leaked!
Only the VERY early Tip-ups had the straight hinges.

 

[az_gila]

Not even shown now...

For the canopy jettison feature, the skins must be notched. Mine have been notched (notches covered with tape similar to what glider pilots use to cover wing root joints) for 15 years. Never leaked!
Only the VERY early Tip-ups had the straight hinges.

The "goose-neck" canopy hinge (Vans terminology......) was introduced in 1992, and the plans now don't even seem to mention or show the "notching option" Mel mentions.

gil A

 

[TX7A]

It's there...

I don't recall seeing the cut-away in the plans, but there is a brief explanation in the instructions for making the cut-away at the hinges.

 

[Mel]

The "goose-neck" canopy hinge (Vans terminology......) was introduced in 1992

1992 is correct. My original finish kits arrived 3/6/91 with the straight hinges. They were replaced with the "goose neck" hinges several months later.

 

[az_gila]

I think it's gone....

I don't recall seeing the cut-away in the plans, but there is a brief explanation in the instructions for making the cut-away at the hinges.

That's what I thought too... but it seems to have also disappeared from the text in my RV-6 2001 plans update package.

gil A

 

[N941WR]

I'm sorely tempted to use an O-235 if it can run auto fuel.

Jonathan, the ability to run auto fuel has to do with the compression ratio, not the engine. There are a lot of O-320's out there running auto fuel and even some of the new, high compression engines now say you can run auto fuel, if it has high enough octane and no alcohol, of course.

Give me a call this weekend, let's go for a ride and talk about things to keep your plane light.

The "goose-neck" canopy hinge (Vans terminology......) was introduced in 1992, and the plans now don't even seem to mention or show the "notching option" Mel mentions.

Gil,

Some place in the plans (New plans, -7 & -9) they tell you to notch the top skin and cover it with a very thin layer of fiberglass so it will break out, should you need to jettison the canopy.

Anyone want to volunteer a built-up canopy for the test?

Hello Doug...

Do you think you could get your friend's at Van's to donate a canopy, frame, and struts and then see if Tony P. has room to deliver it? Then we will need someone who is really good with a camera to take pictures as it rips off the the back of a pickup.

... All in the name of research. You can even tell them there will be no beer involved or animals harmed in the making of the film.

 

[RV7Factory]

On the subject of struts... one of our locals designed a lever system so that the struts could be mounted forward of the panel. The struts are mounted down in the fuse (near the pedals), and when the canopy is closed the lever goes over center and the struts actually help hold the canopy closed. It really is slick, and it keeps the canopy rails free of obstructions.

Now before you go thinking "Why on earth would somebody take the time to do that?" In this gentleman's case there is a definate need to keep the canopy rail clear. I'll leave it at that.

 

[JHines]

Jonathan, the ability to run auto fuel has to do with the compression ratio, not the engine. There are a lot of O-320's out there running auto fuel and even some of the new, high compression engines now say you can run auto fuel, if it has high enough octane and no alcohol, of course.

Yes, I know about the compression ratio and autofuel. My concern is, I was under the impression that the "low compression" versions of the O-235 would put out well below the minimum recommended 118HP, whereas low compression O-320s still put out 150HP. If I'm not mistaken, there is not an autofuel STC for O-235s in certified aircraft, for example. I need to to more research.

 

[todehnal]

Forward Lift Struts

On the subject of struts... one of our locals designed a lever system so that the struts could be mounted forward of the panel. The struts are mounted down in the fuse (near the pedals), and when the canopy is closed the lever goes over center and the struts actually help hold the canopy closed. It really is slick, and it keeps the canopy rails free of obstructions.

Now before you go thinking "Why on earth would somebody take the time to do that?" In this gentleman's case there is a definate need to keep the canopy rail clear. I'll leave it at that.

I think that this is a fantastic idea. It sure would get them completely out of the way and allow obstruction free entry and exit. Also, the added tension in the closed position is another plus. I wonder if there were any negatives to his mod? I like it!!

Tom

 

[RV7Factory]

I think that this is a fantastic idea. It sure would get them completely out of the way and allow obstruction free entry and exit. Also, the added tension in the closed position is another plus. I wonder if there were any negatives to his mod? I like it!!

Tom

I've been meaning to take pictures of it, but I always seem to forget my camera. IIRC, he had to do a bit of engineering for the attach point and he had to order struts of a slightly different length than stock.

 

[jjconstant]

struts with idler arm mechanism

>>I think that this is a fantastic idea. It sure would get them completely out of the way and allow obstruction free entry and exit. Also, the added tension in the closed position is another plus. I wonder if there were any negatives to his mod? I like it!!<<

Tom I'm going to honor Brad's choice of not revealing the gentleman's name until I'm sure I won't be violating something, but suffice to say that this man and his RV 4 were on the cover of Sport Aviation a couple of years ago and the article explained the nature of his need to keep the side rail clear.

I have copied the strut mechanism with his permission and love it. You need to make sure that there isn't anything to foul on the fuselage side by your legs, such as air vent tubing, headset jacks, pockets in upholstery etc. There's a fair amount of room needed for the pivot point of the arms/strut to slide vertically and in a small arc. He also recently mentioned that he added a keeper cord from the center of the rollover bar to the center of the canopy because he felt that his geometry wasn't as strong in potentially resisting a tailwind on the open canopy.

When I'm next at the airport I'll try to remember to take pictures and post them.

Jeremy Constant
RV 7A tip up
wings went on for the first time!

 

[todehnal]

Hidden Struts

Thanks Jeremy. I am glad to hear that this mod has been duplicated, and that you are pleased with it as well. Mine will be built light and with very sparse appointments. So, keeping the areas that you mentioned clear, won't be a problem.

Tom

 

[RV7Factory]

I have copied the strut mechanism with his permission and love it. [snip]

Jeremy Constant
RV 7A tip up
wings went on for the first time!

Idler arm, that's it! For the life of me I couldn't remember that term!

Jeremy, I intentionally kept you (the innocent) outta this, but I am glad you spoke up. I've been meaning to check yours out, but our paths just don't cross that much (at the airport).

 

[jjconstant]

you (the innocent)

Brad

Boy, I'd like to frame that title The folks at work would be howling with laughter

I'll be there on Friday, continuing on riveting the bottom skin on the left wing. Be warned that I force everyone unfortunate enough to come into the hangar into looking at my panel lit up, with no smoke coming out of it!

Jeremy

 

[groucho]

I haven't seen many (any?) RV's with struts how mine are done. I really like it this way (big feet are ok!):

 

[cjensen]

Bryan,

Got a part number or length on those struts?

 

[gasman]

NAPA PART

Bryan,

Got a part number or length on those struts?

Chad......... NAPA part # BK 819-5254

 

[cjensen]

Thanks!!!

 

[jjconstant]

strut mod pictures

Sorry it took so long to get to this.

Jeremy

 

[rzbill]

My 2005 RV-7 plan set has the hinge cutaway detailed as an option

That's what I thought too... but it seems to have also disappeared from the text in my RV-6 2001 plans update package.

gil A

Hi Gil,
Maybe the cutaway documentation is being removed in a "spotty manner". My 2005 set of -7 prints has the cutout as an option.

 

[jjconstant]

Tip up Mod additional pictures

Thanks to whoever fixed my previous attempts at posting photos. I'll try 2 more to give some idea of the strut mod.

 

[jjconstant]

originator of the mod -- Bruce Cruickshank

I've tried to post a video link to show the movement of the mechanism but I've been banging my head against the wall too long. Any help would be appreciated.

I did the video with the originator of the mod moving the canopy up and down. His name is Bruce Cruickshank and I asked if he was comfortable with this getting distributed and if he wanted credit and he said sure. The reason he designed this is that he is a Viet Nam era Marine pilot who became a double amputee after stepping on a mine. This tip up Rv 9 is his second RV. Bruce and his first RV (a 4) were the cover story of sport aviation a few years back.

Needless to say, to lots of us in Livermore, Bruce is our hero, for many, many reasons. Here's Bruce in the lower right of the picture. He is sitting on a removeable trapeze he designed with hardpoints in the wing to help him get in the plane. The picture shows the canopy in the position where the strut is exerting no pressure either to open or close. Any further down is the over-center position and the strut exerts closing force.

 

[jjconstant]

video of mechanism

http://img532.imageshack.us/my.php?image=mvi2535pn5.flv

Sorry for the poor low light quality. It was shot with a still camera in video mode, but I think you can get a feel for the geometry.

Jeremy

 

[cjensen]

Jeremy,

That's a very helpful video, and I thought it was plenty clear.

Can I (we) ask for two more pictures??? How 'bout one of both of the attach points? One of the idler arm attach, and the other of the base of the strut...

Thanks!!!!!

 

[gasman]

Jeremy,

That's a very helpful video, and I thought it was plenty clear.

Can I (we) ask for two more pictures??? How 'bout one of both of the attach points? One of the idler arm attach, and the other of the base of the strut...

Thanks!!!!!

Chad, also ask for the strut part number................

 

[jjconstant]

photos and part number request

Unfortunately, I'm going out of town for a bit and won't be back at the hangar for over a week so I'll try and get that info when I'm back. I plan on arriving at the hangar, scratching my head and saying to myself "...now what the heck was I doing before I was so rudely interrupted by work?

Oh yeah...riveting the bottom skin to the second wing, before mounting them, measuring a thousand times and ways and then drilling the incremental holes for the incidence and sweep. YEHAW! It will definitely feel like progress. Oh yeah...and remembering to grind the corner of the stub off the aft spar on the wing to clear the round head rivet that's kicking it out.

Hmmm...maybe I can use this site as a "teaser" file for the "what was I about to do" moments!

Kind of explains why my friends keep telling me I'm giving "QuickBuild" a bad name

Jeremy

 

[cjensen]

No problem Jeremy...I'm glad you've done what you've done so far!

I'm sure we can all wait patiently...