Making a Rotisserie for the Fuselage - Part 3

As part of my effort to re-engage in building my wings, I needed to order some new Primer. My old AKZO Nobel 2 part epoxy primer, although proven by me to work well enough enough at 7 years plus older than the shelf life date on the cans, is now so old and unused that I have decided not to continue to try to work with it. So I ordered a new can of catalyst and primer - expensive stuff. Picked up a tip from a fellow builder to get 8 empty quart sized paint cans from HD airplane supply and pour the contents into each of these smaller cans to make it easier to pour, store, and prepare. Having had real experience with this in the past by spilling it on the floor while trying to pour in in the small mixing cups,  and knowing precisely how bad smelling and toxic the catalyst is, I think this is a very good idea.

In addition to the primer, I decided I also needed some additional AN bolt hardware to finish the  rotisserie. Each spider leg has two holes in either end of it, and each of those are between 7/16 to 1/2 inch wide on average. With the hole on one end being addressed by the AN3 hardware and wood spacers, etc., I needed to figure out how to attach the other end to the angle. This other hole would normally contain the metric bolts that came with the engine stand. I need to use this other predrilled hole and drill an additional hole somewhere near the middle of each spider to provide the necessary holes to attach the angle iron to the spider.  You need to drill the extra hole in the middle to ensure that the angle is secured in at least two places on the spider arm, so that it cannot rotate out of position.

The next problem is figuring out what length bolts I should use for the remaining holes, to ensure they are short enough so that they do not come into contact with the firewall after attaching each angle to the spider on one end and the center mounting plate on the other. Each of the lugs on the spiders allows for about 1 and 1/2 inches clearance from the firewall. Unfortunately, the metric bolts that come with the engine stand are about 1 1/4 inches long after being inserted into the hole in the spider, so that leaves a very uncomfortable 1/4 inch of free space between the firewall and the angle iron adn spider bar - This is NOT good enough for me. 

SO I need to get shorter length bolts and corresponding hardware. That means I needed to go back to the suppliers and the conversion/identification charts to figure out which AN hardware I should get. My decision, based on measuring hole diameters and lengths and grip requirements and such, was the following:

For the other big hole in the spider and the 1/8 inch thick angle iron that will be attached to it, I decided on either AN7-11A or AN8-11A, since the holes sizes seem to hover somewhere in the vicinity of either one. I order both, and I will see which one gives the better. tighter fit. After I figure that out, I will know what size hole I have to drill in the angle iron.

For the second hole in the middle of each spider to lock the angle iron in place like others seem to have done, I decided to use AN3-7A bolts. Both of these bolt choices should leave at least a half inch or more of clearance from the firewall after being bolted together. That I think I can live with. I also ordered the required nuts and washers for all bolts. The AN7 and AN8 bolts get AN960-716, 726L, 816, and 816L washers, and AN365-720A and AN365-820A, or MS21044N8 lock nuts. The AN3 bolts use the same nuts I already received from Straight Flight, so I think I already have enough of those to use on the shorter AN3 bolts as well.  

I also ordered some hardware that I mentioned long ago in my blog when working on the fuel tanks. I ordered about 50 NAS1352-08-8P cad-plated socket head cap screws to replace the fuel tank access plate screws provided by Vans - AN515-8R8. I have seen too many posts from builders stating how difficult it is to remove Phillips head screws from the access plates of the fuel tanks when you need to service or replace the fuel senders or the fuel line or return attachment hardware or connections. There are 17 of these screws for each fuel tank, so you only need 34, but I always need extras, so I ordered a few extras. Somebody on VAF also asked if a washer would be needed for these cap screws, since their grip width of the head is not as wide as the AN515 screw heads. I am glad he asked that question, as I would never even thought about that. The washer for the cap screw is AN960-8 or AN960-8L for the thin version. I ordered 50 of each of those as well.

My order was shipped from Spruce's Georgia location, and at first I found this to be strange, since most western-based orders are processed by the Southern California location. But on second thought, with southern California's horrible pandemic situation, I am actually relieved that my order came from somewhere else. It also wised me up a bit about hardware orders or any orders for that matter that I will be needing for supplies, parts etc., as I re-engage. I need to be careful about where these are coming from, and develop a process to clean them carefully when I receive them - just to be safe. It is supposed to be here in a couple of days, and then I will resume the work on the rotisserie.

Coming - up - I need to degrease/remove the oil coating from my QB fuse, which now has a layer of fine abrasive forest fire ash particles on it from all the fires in the state this past summer and fall. I have stupidly left this unattended ever since it was delivered to me in 2018. This stuff even penetrated inside the house, so everything is covered with it, inside and out. So this is long overdue, and needs some serious attention. Also coming soon is the upgraded electrical service and heat into my garage. Enough is enough, and I really need to address my hostile building environment this year if I ever want to finish this project. I will also need to order more Proseal and some special formulated sealant for the fuel tank access plates. More on that later.

Busy Preparing for the Fuel Tanks and Tech Counselor Checks out my LE

My Technical Counselor and former long time EAA Chapter 301 President Jim Elliot has been mentoring me through all this LE mod fiasco. I had to wait a couple of weeks for him to become available to come and visit the "almost" finished LE work, and he was finally able to come out last Saturday and take a look. He is a Mooney aircraft owner and has helped several people build different makes and models of experimental airplanes. He definitely knows his way around an airplane, and with evaluating potential affects of modifications such as mine. More on that in a bit.

Since I knew I had to wait for a bit for him to be able to come over, I started preparing (for about the third time now) to get back to work on the fuel tanks. So although I have not posted in while, I have still been very busy thinking, reviewing, and planning for re-engaging on the fuel tanks to get those behind me as soon as possible. his started with a review of many previous posts where I actually started on the left fuel tank because you needed to match it up with the LE to check alignment and drill some holes in the T-712 mounting brackets for the wing spar and the rear tank baffle. This little journey took me clear back to posts from the Fall of 2017. About the last thing I remember about the tanks was fabricating the tank stiffeners for the bottom of the fuel tank skin, and countersinking skin-to-rear baffle holes per the plans.

After reviewing the stuff from the past, I ended up coming up with a list of new additional questions that required answers from Vans. As a side note, to date I have order at least 2 proseal tubes, a small sized can of proseal, and a full sized quart of proseal - ALL of which have shelf lives that have long since expired, so they will not be used to seal any part of my fuel tanks, and I will need to put in an order for more proseal yet again. Sucks to be me I guess - that's about the only way I can sum that up.

Many of these additional questions are questions that you do not see either asked or answered by others, but I find it quite strange that others are not asking the same questions. Anyway, to make sure that I don't lose the content, I am posting them here for myself and anyone else following my blog that might also appreciate the info:

385b and c SW fuel senders - for left and right - is it correct that the potentiometer scale/meter on c version for the right tank will be reversed (facing forward instead of to the rear, when installed on the side of the tank, or should the scale for both still appear toward the rear of the tank when installed correctly.

Vans says this backwards orientation is normal - important thing is that they both point down when installed either on the end rib or the rear baffle plate.

Am I supposed to scuff the back side of the sender flange of each sender if I am going to proseal it directly to the tank rib (NOT use the rubber gasket or cork as recommended by many who have been there before.)

Vans says not needed.

The left sender seems to have a dead spot at the end of travel of the arm (empty indication) - either no ohms reading at all or much higher (300 ohms or more - much higher than expected 240 ohms per the plans.) The right sender seems to be indicating correctly per the palns info. Ordered both SW senders from Vans on 4-16-18 order # 74191. SW says has a 2 year limited warranty - how do I proceed with a replacement. Go through Vans or direct with SW?

vans - Contact SW directly to replace it

Left tank will be flop tubed, so sender will be in bay #2 in rear of baffle.
1. Did I do a lot of extra unnecessary work by cutting the big hole in the aft of the end rib, when I found out that the sender needed to be placed in the second bay via the baffle in the first place.

Vans   -still good to have access t that bay due to the trap door and the flop tube/anti hangup bracket attachments.

2. With the sender in the secnod bay of the rear baffle, that means that the only way I can service that sender if necessary is to pull the entire tank, correct?

Vans - correct - you will have to pull the tank to service the sender that is mounted this way

3. For tank baffle mounted sender, do I need to cut another big round hole in the second bay AND use a reinforcement ring (T-407) as well, or just the hole big enough for the sender to fit in?

Vans says nope - no reinforcement ring or big hole needed - just a hope big enough for the sender to be inserted/mounted directly onto the rear baffle plate web. No reinforcement ring needed because the baffle plate is thicker/stiffer than the rib web.

4. Do I need to use another reinforcement stiffener ring for the T-411 cover plate on rib T-703 if no sender is being mounted in that hole, or can I just mount the cover plate, with nut plates mounted on the rib web itself instead of the combo of the rib web and the reinforcement ring?

Vans - would still use the stiffener ring here as the rib is not very thick and alot of strngth is removed by cutting that big hole.

5. Depth of tank for SW sender specs to determine what size to cut the rod - what dimension should I use for that (tank depth so I cut the rod to the correct length?

Vans - just clamp the sender in place and measure to determine based on the area where the float will be traveling.

6. Since the left tank sender will go in the rear tank baffle, do the dimensions of the float wire change from original plans for mounting in the rib on the side? Any issues with clearance of the bottom stiffeners when mounting the sending in the rear tank baffle?

Vans - measure to be sure, but should not be a change or a problem as far as they are aware.

7. Do you know a part number for a more malleable proseal for access plates that is not as hard as normal proseal to remove??

Vans - they do not use it and did not know the part number of hand - said to check Spruce and others.

8. Grounding the sender - how is this grounded to the airframe if you have the tank baffle or rib web, proseal, and the flange of the sender on the thin later of proseal. Are we supposed to run an additional ground wire from one of the sender mounting screw holes to one of the tank attach bolts or something similar?

Vans - Use a lock nut with the cut flanges that bites into the metal on the underside of the screw head and on the sender flange as it gets mashed down during screw tightening to establish contact for a good ground - so additional wire should be needed, even if screws are prosealed. Do it on all screws or just one or something in between?

As far as the tech counselor visit is concerned, Jim took a look at my unfortunate demise on the LE. Said that it is a dent and not a crease, but that it did deform the outer skin and the subskin. Then we had a conversation about acquiring an autobody or planishing hammer and a dolly that may have to be customized to try to pound (actually TAPPED) out to try to reform the skin back to the shape that it was in before. Unfortunately I can see where my unbelieveably STUPID idea t just keep pounding on the skin with the rivet gun when the rivet was not setting properly has indeed flattened it out a bit. So as a result, if I want to continue with the LE mod using what I have done thus far, I now get to learn a new skill that involves removing dents and reshaping metal, and I probably have to custom-make yet another tool = more wasted time.

So I went to local NAPA store, found a planishing hammer with a rounded head (NOT the kit you find at Harbor Freight, that only has flat headed hammers), and a Toe dolly that, when I fitted it up against the curvature of one of my LE ribs that I took with me to the store, looks like it will almost perfectly conform to the curvature of the LE skin/subskin/rib as long as it is held in the correct position. This is probably going to require a helper to hold the dolly in position while I tap the outer skin and hope like hell that I don't just deform everything beyond reasonable repair.

The last part of our visit was spent having a heart to heart about the possible structural impacts of what I am trying to do, and if I should go ahead and contact a DER (Designated Engineering Representative) to come and look at my invention and provide some further experienced insight on what I am doing. I wanted to go ahead and finish this mod regardless of the ultimate decision about its feasibility, just to see what it would take. At the end of the day I am not certain that this is a safe thing to do, and may still decide to abandon it all together. But I'm not throwing in the towel on the mod just yet.

I've got some parts to order from a number o different vendors so I am also putting that list together. I'll have some pics on the next post that show the damage from the F'd up riveting job  more clearly, and the tools I am going to attempt to use to fix it.

Where have I been since March of 2018?

I know, I know, where the heck have I been March – certainly not working on an airplane much. Crappy weather, house falling apart – same old excuses and interruptions. I did mange to order some prefabbed fuel pick up lines, Proseal, and a few other things, which also went through their own adventure during shipment. Apparently Fedex decided to all but destroy the original packaging from Vans. Admittedly this was rather package to assemble, because I had ordered a big can of Proseal, and I also ordered a replacement .032 x 12 x 3.5 foot piece of sheet aluminum for the leading edge mod on the right wing, since I screwed up the other one that I had ordered an eternity ago.

Even so, all Fedex had to do was put it on plane, then put it on a truck, and deliver it. Easy – right? Yes, until you factor in the sorting equipment in between each of those phases of delivery. Somewhere  in the middle of all that, a sorting machine got hold  of it and destroyed the packing. Amazingly, they did not seem to damage the parts – just the packaging. I knew something was up because my package did not arrive when I expected it to. When it did finally show up, the cardboard was mangled with packing tape, did not look at all like a Vans package, and had obviously been mangled or torn apart somehow. The only damage was a minor bend on one corner of the sheet aluminum that I ordered, but I also noted that Vans had cut it with the grain running the wrong direction.  A call to Vans took care of that, and a few days later I had the replacement part.

Vans wanted me to take pics of the packaging, which I did, and they confirmed that was not the way that it left their facility. Moral to this story s don’t  trust Fedex with anything. I wanted to use UPS but Vans talked me out of it because “they get a better rate with Fedex.” Next time I will use UPS.

A couple of other things have occurred since I last posted. I had wanted to get a new travel trailer, and decided that this year was the year for that to happen. I wanted something a little newer and larger, with built in air conditioning and a nicer master bed. Not hard to find a better bed, since I had been sleeping on the couch for years. While I was pursuing a new trailer, my truck decided to start nickel and diming me. Time to make a decision – so I spent the past several months researching trucks and trailers, and ended up getting one of each.

Then, as if that was not enough, I decided with all the delays in the plane build that I needed to bite the bullet again and order a quickbuild fuselage for my RV-8 from Vans. So, in the past few months I have acquired a new trailer, truck, and 75% complete airplane fuselage.  Oh, and I also spent the past 2 months trying to sell my old trailer, which finally did sell about a week ago.

To top it all off, work has been a nightmare – that’s about all I am going to say about that. So here I am, several months later, a LOT poorer, completely exhausted, and oh yes, I am writing this in Oshkosh Wisconsin after making the maiden voyage in my new-found ground-based travel machines.  I have been running non-stop for months now and I am completely exhausted. I only had time to throw everything from the old trailer into the new one wherever it would fit – no time to organize. More about the shakeout of the new rig and all about the Airventure 2018 journey in the next posts.

Called Vans again to get answers to yet more questions about fuel tanks

Q: How to finish securing the the trap door hinge pin?
A: They just bend one side of it (the side toward the rear of the rib, like I have already done). They depend on the joint between the rear baffle and rear rib flange as a hinge stop and don't even bother bending the other half.

Q: How to fabricate the rear-most anti hangup bracket for the flop tube assembly? I asked because the small drawings were not clear how this was supposed to be designed, and they do not provide any instructions for it either.
A: you can twist/bend it so that the face of the bracket is properly oriented on both the stiffener and the rib web. they said that using an "angle" is probably overkill. So attach one end to the stiffener and then twist/bend it forward enough so that the other end of the bracket is properly oriented 90 degrees from the other end.

Q: What thickness material and rivets to use to cover up the t-704 hole in the rear web of the first inboard tank rib. Needs to be done since all main fuel flow into this bay of the tank is supposed to be controlled ONLY by the hole in the lower rear of the rib where the trap door resides.
A: Use whatever scrap you have and put 4 rivets of your choosing to permanently cover with no proseal or anything - just cover that hole so the majority of the fuel entering that bay must come through the bottom hole with the trap door.

There are several other smaller tooling holes in the rib that will also allow fuel to move through them, but they are so small that they shouldn't matter much.

Q: Use the tank dies or no?
A: Says you are supposed to use the tank dies on the ribs, and the regular dies on the skins.

I don't think this is correct per Mike at Cleaveland Tools - I told the guy at Vans about a video that MIke had finally produced where he attempts to cover the proper use of the substructure dies, tank dies, and regular dies. I need to review that video again and make my final decision about which dies to use on which parts.

Q: Proper washer placement for the AN fittings for the flop tube?
A: There is no spacer(washer) placed on the T-405 tank attach bracket because that part already basically serves as a spacer since it is 3/16ths of an inch thick. So I just need to fab the part, cut small recesses in it where the rib flange/skin rivets are located around the very front of the rib, place the nut on the part and mark the rivet hole locations as best as possible to ensure clearance around the nut so that it can be secured with a wrench later on, and the nut is the only thing that rests against the face of the attach bracket.

Then my friend Mike Rettig supplied me with a few more answers to some Proseal questions:
Q: Buy and use the 1/2 inch wide x 1/16th inch deep spouts for the SEmco tubes to apply a coat on each rib web, or just use the circular tube tat comes with each tube?
A: Just use the circular applicator tube that comes with each tube, apply the bead on the rib flange only, and NOT the skin, and use a pop sickle stick or other applicator to spread it evenly across the width of the flange.

Then attach the ribs to the skin per Rick Gialotti's faying method as posted in VAF.

SO to finish up the trap door tomorrow I will shorten up the other end of the hinge pin, smooth it out, and proceed with making the cover plate for the other hole and riveting that in place.