Ron Springer

If the numbers are correct, then they mixed the MGS incorrectly. The correct weight ratio is 100:40 (+/-2), so they were even outside the tolerance.

The math tells me that she could sit in the back seat.

The photo shows the plane when it was in service. Apparently, the company needs to update their website. http://www.image-america.com/

I used a strip of wood that was a couple inches wide and covered in box tape as a dam. I only bondoed at the bottom of the strip. It was sturdy enough, but not a perfect seal. So, I put a flox fillet in the corner formed by the dam and shear web when I did the spar cap to prevent epoxy runs. It mostly worked. Keeping the flox a little dry helped. It sounds like you have a bondo fillet instead of a flox fillet there. If you can remove the bondo without damaging the spar cap tape, then you can replace the bondo with flox and your result will be no different than mine. It is OK to make a fillet there of flox. Spar cap tape does not have to fill the entire triangular corner area. If you are concerned that you damaged one or two layers of spar cap tape by removing the bondo, then you could always add another ply or two on top of your current spar cap. That would add weight and thickness, but sometimes you just do what you need to do for peace of mind. But, you couldn't have damaged much of your spar cap if the depth of the groove is only 1/8" deep and most of the removed material was bondo.

Good post, but I find this statement a little difficult to believe:

Lift is defined normal to the velocity vector, not normal to the chord. I will also make an attempt to explain the winglet thrust in simple terms ... The velocity vector out at the winglet has two components. The main component has the magnitude of the velocity of the plane pointing straight aft and opposite to the direction of flight. The second smaller component is pointed inward (above the wing, outward below it). That component is due to the tip vortex. Try to visualize the vortex rotating around the wingtip from the bottom to the top and how the small component of velocity is created. So, even if the winglet points straight forward, it is still at a small angle of attack. If the velocity points mostly aft but slightly inboard, then the lift acts normal to it, which is mostly straight to the side but also slightly forward. The small forward component of winglet lift is a thrust component. It probably isn't much thrust, but it is greater than zero!

That paper would be a good read. AIAA sells it for $25. Another option is to get a copy at the library since it was printed in the 1983 Journal of Aircraft. Just need to find a library that carries it. It am almost certain it can be found at the NASA Langley library, so I'll volunteer Wayne Hicks for the task!

I guess I have a short memory. There were at least four posts on the Cozy list on June 2, 2006. Richard Riley dismissed this issue. He stated that the foam density can vary widely and that what Wicks and Aircraft Spruce sells is essentially the same stuff. The density can vary from 1.6 to 2.0, or 1.8 +/- 10%. Maybe I'll go get a large scrap and weigh it and then calculate the density to see what it really is ...

I just finished my canard out of foam purchased at Wicks. So, it is the 1.6# foam. Guess I haven't checked the archives well enough, because this is the first I have heard of the issue! On the other hand, there must be a lot of planes out there built from this foam. I think they have been selling it for some time. I am almost positive that Dennis Oelmann buys his foam from Wicks because they seem to know him pretty well. He certainly cranks out a lot of canards and wings. Featherlite on the other hand does not get their foam from either Wicks or Aircraft Spruce. They get their foam from a place local to me in Sacramento. I guess that is probably where I will be buying my foam for the wings.

My modification of the plans method did not involve a 2"x10" board. I assembled on top of my table, which I lowered to the floor. I just drew a centerline down the table and then attached the 2x4s to it.

So, basically you had to jig the fuselage for both the upside down method and the right side up method. So, there is extra work involved. This wasn't a factor since I would never depend on gravity to hold the bulkhead in place during cure. The landing gear bulkheads were clamped in position during cure with the appropriate spacers. Well, another factor is that I knew my table wasn't perfectly flat. It is within plus or minus 1/16" over 12 feet, but not perfect. There is also a slight twist to it. By assembling right side up, I didn't need to worry about it. If your table is perfect, then you won't have this problem. I second that! But, I don't have to adopt every suggestion on his web site.

I did mine right side up. I have a one foot thick table top with no legs. I use saw horses to support it. Instead of saw horses, I set it directly on the floor and made it level. Then, I attached the 2x4s and drew a centerline. I clamped F22 and the temporary firewall in position to level the longerons. Once clamped, the longerons stayed level for the rest of the process. I didn't find it difficult to make sure they were in the same plane. I was able to check for level lengthwise along the longerons and also diagonally across the fuselage. Since I had a flat table reference plane, I was able to use a square on the table to make sure the bulkheads were vertical. So, I went against the latest trend in fuselage assembly and did not encounter any problems. There are a lot of claims that it is easier to do it upside down, but few people have done it both ways. So, it is just an opinion. I had to attach a couple 2x4s to my table instead of cut a hole in it (and repair it later). After that, I don't think the workload is any different. So, I would argue it is easier to do it my way. (Alright, I'm going to go hide from Wayne now.)

What trim tabs will be done away with?

Actually, I recommend that (doing one side at a time), especially if working by yourself. Doing both sides at the same time amounts to approximately four times the front seat area, and the contour is not flat like the seat back. You will spend a lot of time getting the cloth to follow the contours without bubbles. It can be overwhelming to do both sides at once if you are not prepared.

I followed someone's recommendation to have equal overhang on the jigs at each end when bending the longerons. And, then again have equal overhang when attaching the longerons to the sides. The bottom line is that the doubler must be far enough forward for F-28. And, anything forward of F-28 gets cut off later. At the aft end, you must have enough doubler to get through the firewall. It all worked out when I followed the above recommendation.

Also, there is no magic to the 7/8". You probably have some leftover lumber laying around that is 3/4". Nothing wrong with using it.

I ordered about 2 gallons worth of MGS 285 about six months ago with slow and fast hardener and it was shipped ORM-D and shipping was not expensive. This order was from ACS and shipped within CA. Maybe ORM-D means to treat it roughly, because the box was ripped and broken apart when it arrived. The epoxy was lucky to have stayed inside! But, it made it and it was cheap. I went to order another gallon today with a can of slow and fast hardener. I notice there are now hazardous item icons all over the online order screen for each of these. So, I called them up. The lady on the phone said that hazardous item charges can be avoided for my items if less than 4 liters is shipped. So, I placed the order and asked them to split the order if needed to avoid hazardous item charges. Later, I get an email from ACS saying that the resin and fast hardener can be shipped without hazardous charges. However, the slow hardener is special and hazardous charges apply in any quantity. Anyway, this entire shipping classification issue is confusing and I get different answers from different people. I'll have to remember to stock up next time I drive down to LA. So, did I just get lucky the first time, or has something changed?

Part C installs between the aft LG bulkhead and firewall. The tapered edge points up (when the fuselage is upside down). The inside surface of C should basically be an extension of the inside surface on your fuselage sides. Make it flat and put something there temporarily while it cures. Adjust the taper and size of C to fit the curvature of the two bulkheads. Part D also has a tapered edge that when installed touches the tapered edge of part C. It spans between the bulkheads and over to the foam for the NACA scoop. I am not sure where you feel that this interferes with the Chapter 9 layups?

Waiter ... thanks for the good info. I originally assumed it would not be a problem to breathe the compressed air with a pressurized mask. But, I was not aware that the lungs cannot hold much above 1.5 psi over ambient, or of the comfort level in doing this type of breathing. So, to breathe compressed air comfortably you would need a pressurized suit, and I am sure that would be expensive and uncomfortable to wear too. Sounds like there is no comfortable solution other than pressurizing the complete interior of the plane with compressed air.

If you did choose to pressure breathe compressed air at up to 18,000 ft as you suggest, then it would open the possibility of not using a bottle of compressed air at all. You could make your own on the fly using an engine driven compressor, or bleed from a turbo or supercharger if you have one. It is best if it is oil-free though!

Well, I believe that you could use pressurized air when flying. But, you will be carrying a bottle that is full of 79% nitrogen, which is a big waste. You will need a MUCH larger bottle. There is plenty of nitrogen available at the altitudes we fly, so why carry it along? For scuba diving, you can't breathe 100% oxygen, and there is no nitrogen available, so you have to take it along. For some dives, nitrox is used, which is 50% oxygen and 50% nitrogen.