Sig Morrisey Bravo Build
#502
Thread Starter
So I want to tell you about something that has had me confused for the past few days...
Waiting for epoxy or glue to dry often gets me to start other tasks in the build process now that I have a much larger build table. So a few days ago, I decided to frame up the vertical stabilizer. I don't know if you build like me, but often I just look at the plans without looking at the instruction booklet and start framing things out. Making note of the dimensional wood I need off the plans, I go to the "wood pile" and select all of the materials that I need. In this case, most of the vertical stabilizer is framed with 5/16" x 1/2" stock with only a small lower portion of its base to be clad in 1/8" sheeting, the rest is left open to get covered in whatever material (fabric or plastic) that you choose. Nowhere in the kit did I find any such dimensional stock. I know I didn't lose it, it's possible that it got lost over time especially considering the age and multiple owners of this kit. (5/16" stock is not easily found today at LHS these days.)
It was also curious to me that other builders (through photographs) built their stabs differently. It appeared they all sheeted their entire stabilizer, or so I thought. I didn't think much of it at the time. It was also puzzling to me that I had left over two 3/8" thick printed sheets that I couldn't figure out where it went. So at this point I decided to read the instruction booklet. It made no mention of sheeting the stab, and it made no mention as to what the left over 3/8" printed wood was for. Then I had an idea, I looked at the printed wood and it appeared that if I cut out and assembled the pieces together that it would resemble the stabilizer. So I think I have solved my dilemma, the entire vertical stabilizer is made from this solid 3/8" thick Balsa and that there must have been revisions made to the plans. I must have the first "original" type of plans! I have since investigated and checked with other Bravo plans and sure enough it shows up differently. Mystery solved!
I hope that this helps others that might have the same problem...
Waiting for epoxy or glue to dry often gets me to start other tasks in the build process now that I have a much larger build table. So a few days ago, I decided to frame up the vertical stabilizer. I don't know if you build like me, but often I just look at the plans without looking at the instruction booklet and start framing things out. Making note of the dimensional wood I need off the plans, I go to the "wood pile" and select all of the materials that I need. In this case, most of the vertical stabilizer is framed with 5/16" x 1/2" stock with only a small lower portion of its base to be clad in 1/8" sheeting, the rest is left open to get covered in whatever material (fabric or plastic) that you choose. Nowhere in the kit did I find any such dimensional stock. I know I didn't lose it, it's possible that it got lost over time especially considering the age and multiple owners of this kit. (5/16" stock is not easily found today at LHS these days.)
It was also curious to me that other builders (through photographs) built their stabs differently. It appeared they all sheeted their entire stabilizer, or so I thought. I didn't think much of it at the time. It was also puzzling to me that I had left over two 3/8" thick printed sheets that I couldn't figure out where it went. So at this point I decided to read the instruction booklet. It made no mention of sheeting the stab, and it made no mention as to what the left over 3/8" printed wood was for. Then I had an idea, I looked at the printed wood and it appeared that if I cut out and assembled the pieces together that it would resemble the stabilizer. So I think I have solved my dilemma, the entire vertical stabilizer is made from this solid 3/8" thick Balsa and that there must have been revisions made to the plans. I must have the first "original" type of plans! I have since investigated and checked with other Bravo plans and sure enough it shows up differently. Mystery solved!
I hope that this helps others that might have the same problem...
Last edited by VincentJ; 03-21-2017 at 12:34 PM.
#503
My Feedback: (6)
Nice catch Vincent! Now comes the question from a weight saving point vs. strength point of view which system is better? Is a solid stab better than a built up stab? If the stab has an airfoil shape is it easier done with a built up or by sanding a solid piece? From a scale point of view which looks better? I know I'm opening the jumbo large economy size can of worms here but is there a better place to debate this when we have so many builders watching?
I will say on I have built stabs with solid sheets and a frame work. In the end I lean more toward a hybrid with a center balsa sheet with ribs on both sides with shaped edges to give the final shape. This can be planked or covered depending on the airplane being modeled.
Mike
I will say on I have built stabs with solid sheets and a frame work. In the end I lean more toward a hybrid with a center balsa sheet with ribs on both sides with shaped edges to give the final shape. This can be planked or covered depending on the airplane being modeled.
Mike
#505
Thread Starter
If you compare photo #1 (my plans) to #2, you will be able to see the differences in how the stabilizer was built compared to how it's now built. Photo #3 are the 3/8" thick printed Balsa sheet stock that will ultimately become the solid stab. Other than the more obvious, the leading edge went from 5/16" x 1/2" Balsa to 3/8" x 3/4" Spruce. My guess is that this was a weak point in the build that they corrected for. I now have all of the materials to finally build my stab! My new mystery to now solve, why do I have two sheets when I only need one??
Addendum: One more thing to clarify. If you go back to first post in this thread, take a close look at the second photo by increasing its size. Look carefully at the bottom center of the kit box. Can you read the hand stamped blue printed words? If you can't it reads; "MODIFIED TAIL". This further explains the revisions made to the tail in the kit. In my case, they (SIG) somehow forgot to replace the instruction booklet and plan with the newer version. Case closed!
Last edited by VincentJ; 03-23-2017 at 05:37 AM.
#506
I chuckled to see on the newer version of the plans the Fin Cross Section diagrams that don't just show you the proper leading edge shape, but give Wrong, Better, and BEST examples the profile. The don't give you any excuses for getting it wrong.
#507
Thread Starter
Mike, your absolutely right that a traditional rib constructed fin planked would be lighter and strong as one made from solid Balsa. It may also resist warping and twisting better. In my case, the 3/8" Balsa used for the fin is pretty light. I don't mind sanding it to its final shape, I don't have to plank it and I don't have to add blocking for the hinges, so that's what I'm going with.
Tim, I got a laugh from that as well when I saw it. I'm glad I got all that sorted out because it was driving me batty!
Tim, I got a laugh from that as well when I saw it. I'm glad I got all that sorted out because it was driving me batty!
Last edited by VincentJ; 03-22-2017 at 05:27 AM.
#508
My Feedback: (6)
Mike, your absolutely right that a traditional rib constructed fin planked would be lighter and strong as one made from solid Balsa. It may also resist warping and twisting better. In my case, the 3/8" Balsa used for the fin is pretty light. I don't mind sanding it to its final shape, I don't have to plank it and I don't have to add blocking for the hinges, so that's what I'm going with.
Tim, I got a laugh from that as well when I saw it. I'm glad I got all that sorted out because it was driving me batty!
Tim, I got a laugh from that as well when I saw it. I'm glad I got all that sorted out because it was driving me batty!
#509
Thread Starter
As you can see the top 1/8" sheeting has been completed. The cockpit area was also roughed out, a bit more of a gradual sweep may still be needed. I even had the time to notch out the landing gear plate, doing this will give the two wing dowels the clearance it needs. Before the landing gear plate is epoxied in place, I will drill the three holes for the aluminum landing gear and install the "T" nuts. Before long she is going to have some legs!!!
Last edited by VincentJ; 03-24-2017 at 03:14 AM.
#514
Thread Starter
Correct on all counts Tom! I'm not in a rush and I suspect you're a lot like me in that you probably enjoy the building aspect a bit more than the flying...you can correct me if I'm wrong. Not that it isn't satisfying to fly because it does bring me joy as well.
#516
Thread Starter
Well Tom, I was glad I wasn't drinking coffee when I read your post because it would have been coming out of my nose I laughed so hard!
When I got home today, I thought I would get the landing gear block epoxied in place so I wouldn't have to wait for it to dry tomorrow since I am not going to work. It's worth the time to make sure the gear is mounted absolutely "dead nuts" square on the block so the plane will track straight later.
Photo #1 shows the layout lines and where the three (10-32 Allen head cap screws supplied in kit) holes are to go. I used my drill press to ensure the holes were drilled straight. (Note: I used some scrap wood under the gear block to prevent tear-out.) Placing the block back into position, I noticed that both tri-stock pieces we going to interfere with the two end holes. Photo #3 shows the outline of the holes. With the block back in position I used the already drilled straight holes of the gear block to guide me with my electric drill to drill (photo #4). The block was once again removed and "T" nuts were epoxied in place. To ensure none of the epoxy accidentally got in the threads, I rolled up some tape and placed them in the "T" nut openings. Add a few clamps for holding power and I'm done!
Last edited by VincentJ; 03-24-2017 at 01:59 PM.
#518
#519
Thread Starter
Much more to report on...
Plans call for a 3/4" thick 4''x 8'' Balsa nose block epoxied to the bottom of the fuse just ahead of the landing gear. I'm opting for this nose block to be removable which is why you see ( photo #1) the additional framework clamped in place, it will be held using four 4-40 cap head screws.
Next I glued two Basswood cowl mounting blocks ( photo #2 ) to the right and left hand sides of the firewall, more on that later.
Photos #3-8 show what I came up with to hold the ignition module against the firewall. I bought a piece of 1/2" aluminum angle stock at my local hardware store and cut two pieces the length of the ignition box. I drilled several 1/4" holes down the side of each bracket for two reasons, one to save weight, and second, to zip tie the box against the firewall. Two small #1 Phillip head screws hold the brackets in place. I made sure to countersink the holes so the screws will sit flush against the bracket. Photo #8 shows the module temporarily held in place with only one zip tie, two will be used in the final installation along with a piece of foam beneath the module.
The rest of the photos show some of the steps I went through to get the cowl fitted. There is no secret for fitting a cowl, except that you have to take your time, take small cuts and constantly keep rechecking for fit. If you don't take the cowl on/off at least 30 times (I may be exaggerating) you're taking chances cutting off too much at one time. In the end, if your measurements were accurate you will not end up with any unpleasant surprises.
I am using the stock Sig supplied fiberglass cowl. There is no need to buy a cowl, as the quality of the one supplied in the kit is excellent. If you are in need of an additional cowl, I suggest purchasing one from Fiberglass Specialties. http://www.fiberglassspecialtiesinc.com/
Safety note: Be sure to wear a good dust mask to prevent inhalation of dangerous fiberglass dust while cutting and grinding your cowl! I usually have my shop vac on with its nozzle pointed at what I'm cutting to help keep the dust at bay.
Last edited by VincentJ; 03-27-2017 at 05:16 AM.
#520
Thread Starter
Spent most of the day with my wife , but somehow I did find myself in the workshop for a couple of hours.
I thought I would get the cowl mounting done. I am going to use something a bit different to secure the cowl in place, specifically brass Thread Inserts. These inserts are for 4-40 screws, but they do come in other larger sizes. They couldn't be simpler to install, just drill and thread them in place with a flat bladed screwdriver. They will be removed later and I will put some epoxy on the threads then reinstall, making them a permanent fixture. I decided to go this route because I tend to remove the cowl a lot and I wanted something that wouldn't wear out quickly. I think they will do the trick! I am pretty pleased with the transition lines between the fuselage and cowl. Notice, there are four holes on each side of the cowl, two are used to secure the cowl to the fuse, the others will have "dummy" screws to simulate a scale detail that the original Bravo had (see photo on page 1, post #15) .
Last edited by VincentJ; 03-27-2017 at 03:23 AM.
#521
All the time off never put a crimp in your style, very precise in all aspects and there's nothing wrong with that. I will check in every so often, always did enjoy seeing your work.
Leroy
Leroy
#522
Thread Starter
Thanks Leroy, it's been a while for sure...taking the time off was the right thing for me to do. Glad you stopped by, don't be a stranger! I always like your discerning eyes to check over my work.
Last edited by VincentJ; 03-27-2017 at 04:52 AM.
#525
Thread Starter
Don't you just love it when you see the UPS truck pull into your driveway! Of course in my house that usually means that the wife bought something , but this time it was for me! My IBEC arrived along with my 3" spinner.