Re: Project 5 build thread
Dang, I envy your CAD skills. I might need you to talk me through adding a part to my panel drawing and positioning it in the right place...
Just watched your latest video. Sure wish I had known that you needed more clecoes. I bought two bags of 100 years ago when Brown Tool had some blemished ones on sale really cheap (I was hard over on building an RV-8 at the time). I could have given you a bag and still had a lifetime supply!
Re: Project 5 build thread
I would have taken them too. I recently realized that one should have at least two batches of Clecos. A dirty set and a super clean set. Once you get parts all meticulously clean it doesn't make sense to jam greasy Clecos in the holes.
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Re: Project 5 build thread
I just learned a few minutes ago that my Verner Scarlett 7U is in production and will soon be headed to the test cell for a six hour run.
I'm stoked. This is about a month earlier than predicted.
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Pretty soon I'll be filling this hole.
Re: Project 5 build thread
Woo hoo! I'm definitely going to have to stop by for a gander when it arrives.
Re: Project 5 build thread
Quote:
Originally Posted by
alexM
I just learned a few minutes ago that my Verner Scarlett 7U is in production and will soon be headed to the test cell for a six hour run.
I'm stoked. This is about a month earlier than predicted.
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Pretty soon I'll be filling this hole.
Hey Alex, how exciting!!!!! I'm as well, stoked for you!!!
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Re: Project 5 build thread
Yesterday I got the last of my lift strut attach fittings bonded/riveted in place. Planning on a good build session today where I will re-fit the wings to the spar carry through, removing just enough material to account for the steel doublers which are inside the spars. Then I'll cut the reliefs in the aft spars to allow wing sweep, and finally hoping to get my #1 ribs bonded in place.
It's a lofty goal but I should be able to at least get all that done this weekend.
In the meantime, here are a few more "work in progress" shots of my instrument panel. I need to place the stiffening angles on the back side and it looks like I'll need to make a slight adjustment in spacing but only about 1/8". I'm even showing the nutplates I've purchased to retain the display units, including the countersunk rivet locations.
I'm looking forward to getting my fuselage back on its gear so I can sit in it and mock this panel up, make some airplane noises and see if I need to move anything. I may end up adjusting the spacing of the displays, move switches, etc.
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Still using my free seat of Solidworks, courtesy of an EAA membership. The above image includes my custom screen pages I created with the MGL software. That is pages 1 and 3 showing as I imagine for a pilot sitting on the left while enroute. EFIS and engine information on one screen and moving map on the other.
Those custom screen pages are also still in draft form. I'm mostly happy with them but still have some work to do. For those who are going to zoom in, things like the G meter will only pop up on the display above 1.5G and below 0.5G. Other fields like the climb/glide ratio and angle will be removed after phase 1 flight testing.
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Re: Project 5 build thread
Alex, Great job using that solidworks! So with 7u and the fuel system, I'm assuming there is no fuel pump on the motor, so are you running just one electric fuel pump or the two as back up?
Re: Project 5 build thread
Quote:
Originally Posted by
Freedom2
Alex, Great job using that solidworks! So with 7u and the fuel system, I'm assuming there is no fuel pump on the motor, so are you running just one electric fuel pump or the two as back up?
Great question, to which the answer is "it depends". To set the stage for the passively interested reader, at the time I was preparing to order my engine there were three induction options available for the Verner radials. A simple SS side draft carb which has no mixture control (good to about 6500' MSL according to the literature), a Marv Schebler carb identical to the one my Citabria had, and a throttle body fuel injection system.
I was leaning towards the fuel injection system but as I got closer to ordering my engine that option was removed. Brett Hahn, the US importer I'm working with, told me it wasn't because there was a problem with the FI system, it was because so many customers screwed with it (changed fuel maps and settings) and expected support and hand holding while doing so. It became a significant time sink for the folks at Verner so they removed the option.
I've spent quite a bit of time on the phone with Brett. He and I are both motorcycle riders and gear heads in general. He knows that I plug a laptop into every vehicle I own and understand the process and has discussed that with the factory. If there are any warranty or service bulletin issues with my engine they are comfortable sending me the parts rather than requiring the engine be shipped back and forth. I probably could have still obtained the FI system, but opted to go with the Marv Schebler because it was a known quantity for me.
Back to the fuel pump question. With both carb versions it only needs about 0.5 psi of pressure head at the carb, and we all know that planes like my Citabria make due with gravity feed from the tanks and they do fine with no fuel pump of any kind. The carb on your typical horizontally opposed engine is underneath, but the carb on a radial is directly aft of the center of the crank shaft (so a bit higher). You can look at the history of the Luscombe and see where early installations of 90hp engines resulted in a much steeper climb out, bringing the fuel tank to the same height as the carb.
Zero fuel pressure degrades climb performance by roughly 100% when the engine dies, so presence of a fuel pump for prime, engine start, takeoff and climb are warranted and that is what I had planned for up until now. I will note that the factory installation manual calls for 2.2-10.1 psi for the carb engines so they expect a full time fuel pump.
There's always a "but"...
When Brett called me last week to tell me my engine was being assembled there was a "but". It turns out that Marv Schebler carbs are in short supply in the Czech republic, so my engine will go into the test cell with the side draft SS carb and it will ship that way to me. Apparently 90% of customers go with the SS and it works great. It would also work great for 90% of my flying, but there's the Cascade range between me and a lot of places I go so I would prefer a red knob be available.
Brett told me he has been installing a different throttle body fuel injection system on the Scarlett 9 engines and is having excellent success with it. He has not yet installed TB FI on a 7 cylinder so he is willing to cut me a deal to be the test mule for it. That system does run a pair of fuel pumps, just like the FI Rotax engines do.
Presence of the FI system comes with one obvious benefit, and that is that it removes an engineering challenge of providing carb heat. I was going to have to create an air box with a flapper door and run a push-pull cable to my panel.
Re: Project 5 build thread
Wow, did I dig up a can of worms! MMM, I guess time will tell where I end up going with this?? thx for that info on this subject, I'll stay tuned.
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Re: Project 5 build thread
I just had a pretty productive day. Made a big dent in my lofty goals mentioned earlier and hit a big milestone, and I also got a cool part from Kitfox today!
Heather emailed me early last week to tell me that my carbon fiber boot cowl had just shipped. That was a pleasant surprise because I didn't expect it for a few months. A while back I sold my fiberglass boot cowl to Eric in order to complement the 912 SS7 style upper/lower that were on the chopping block. I retained the stainless firewall for the 912 as the basis for my Verner installation.
I haven't seen all the possible firewall/boot cowl versions available but at least some of the cowlings I've seen for the Lycoming and friends have a "step" or blended joggle in them to accommodate the wide air cooled engines. Some other versions I've seen have the upper cowl go all the way back to the windshield, which seems like a pain in the a**. For reasons I'm about to explain, the SS7 boot cowl is a pretty good starting point. And for the naysayers it will also mean that the plane I build will be (close to) drop in ready for a 912 FWF.
I have a task ahead of me which is to fabricate the section of cowl from the firewall to the back of the exhaust system. It has to blend from the shape of the firewall to a 32-ish" circle in about 13" (pulling numbers from memory, subject to fact checking). The way I pull that off (metal or fiberglass) is still TBD, but I did want my boot cowl here about time my engine showed up so that I could start this work.
Where was I?
The delivery truck showed up this morning about 10am. A very nice guy gets out and opens the back of the truck. He puts on his gloves and starts pumping the handle of a pallet jack. In the back of the truck is a huge box on a pallet but just ahead of it I see another box which looks light, and it says "Alex" on it. I tell the driver but he said "Yep, there are two Alex's on my route today". He checks his paperwork and confirms the reasonable sized box is not mine. And that what looks like a Chevy crate motor is.
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The driver was a nice guy and curious as I start cutting the straps holding the lid to the pallet underneath. There was enough dunnage to stage a shipwreck, but the part was in perfect condition. We both had a good laugh over the weight of the part when I handed it to him.
Speaking of which. 2 lbs 4.5 ounces. I asked Eric just the other day if he had the means to weigh the fiberglass version I sold him. The answer was 4 lbs 2.17 ounces, so not quite a 2 lb weight savings.
Back to the hangar
I suckered my youngest son into helping me today. I can get the wings on and off by myself now, and it's not that hard. But in order to file the vertical tubes in the spar carry through to fit over my steel doubler equipped spars was going to take some filing, a test fit and removal, some filing, etc - over and over until the wings could be pinned again. By having his assistance I could make a round trip every five minutes if necessary. Whoever started my project had filed the tops of the vertical tubes in the spar carry through but left the bottoms untouched. Since I rigged the wings with the spars touching on the tops I figured I would only file on the bottoms this time, which should leave my rigging in a good spot.
Once we got both wings fitted so they would pin again at the roots I turned my attention to cutting the notches in the aft spar to allow the wings to fold. I started with the stump I cutoff the scrap wings and figured out where they removed the right and wrong amounts of material. Then I used some file folder paper to make a perfect sleeve that fit over the stump, left just enough room to allow the wing to fold and included the holes to locate the cut edge.
It was perfect, except that I made it for a spar tube that didn't have steel doublers riveted and bonded on. So I made another file folder sleeve, this time fitting it over the uncut spars, and taking a SWAG at transferring my previously derived shape to the larger sleeve.
I cut the relief notch on my right wing, mostly with a 2" cutoff wheel on my 12V Milwaukee straight grinder, but also used a 3" cutoff wheel on an air motor. I stayed inside the sharpie pen marks on the spar because it's always easier to remove more material than to put it back. On the left wing I had to think about it for a while and came to the conclusion that to mirror the notch on the right I would have to remove the tape on my paper sleeve and turn it inside out.
Ever have that feeling that you've been grinding away on the wrong part of the wing spar? Well I did, about four times per wing. But every time I stopped I was doing it right, so I kept at it.
Next we notched the #1 ribs so they would slide over the steel doublers, then I slid them on all the way up to the #3 rib so I could attend to them later without pulling the wings off.
Finally it was time to pull the fuselage outside and put the wings on. I could have done that part in the hangar but I could not have checked the wing sweep because it's a T hangar. Between my practice doing the job alone, and having my son there we made quick work of it. Before I could do that however, we had to put the landing gear back on. He's helped me with that before so it didn't take long.
For the record, the plane will not fall over with just one wing on it (at least at this stage of the build). With both wings on it was time for a photographic high five moment, so that's what you get below. We checked the wing sweep and I have some material to remove. Basically my sharpie marks are right on if I just grind until they are gone too. Again, this was a planned outcome because I don't want to remove more than I need to.
Anyway, this was pretty cool for me to see this afternoon. I successfully made my way through the slow wing build and rigging process. I'll head back over tomorrow to bond the #1 ribs in place.
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