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Old May 29, 2011, 09:02 PM
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Staggerflyer's Avatar
Tama, Iowa USA
Joined Dec 2007
575 Posts
Got my storage space straightened up, so brought the Tigercat's fuse up to the work table to check out the damage. Glad I didn't go flying this afternoon. The wind finally stopped blowing at hurricane strength about 3pm this afternoon, but it is still cloudy and ugly. Anyway, here is what I found after close inspection and pulling on the pieces, including pushing downward slightly on the tail section.

#1. The former that forms the rear of the wing saddle was broken. The ply had separated on all three sheets from each other. (This is the area I mentioned to you, Rocketman.) This occurred on the right side. The left side is still good.

#2. The left side longeron is still glued to the former on the left side, even though that side is missing part of the former. The right side, which still has all the wood, is completely separated from the former! It was never glued!!!

#3. The right side longeron was never glued to the wing saddle former!

#4. The two soft balsa stringers along the inside of the upper spine and the two small carbon fiber stringers are all that tie the tail assy to the front of the rear wing saddle. In other words, the skin is ALL the strength there. Hi G manuevers NOT recommended!! It's hard to see, but I am squeezing the areas in the center of the two long balsa stringers, where the arrows are pointing. You cannot feel the stringers because they are so soft. (Read WEAK!)
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Old May 29, 2011, 11:03 PM
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TripleW's Avatar
Prescott, Arizona
Joined Feb 2010
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What are you gonna use to glue that back together? TW
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Old May 29, 2011, 11:38 PM
Cut the yellow wire
CarreraGTSCS's Avatar
United States, NJ, Trenton
Joined Jan 2004
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I had a fiberglass fuselaged glider a few years back that was pretty soft in the aft portion and I drizzled brown Gorilla glue into the areas that needed reinforcing then sprayed some water in there with it. Causes the GG to foam up. Really stiffened the fuselage. Does not add much weight either.
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Old May 30, 2011, 05:07 AM
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Staggerflyer's Avatar
Tama, Iowa USA
Joined Dec 2007
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Quote:
Originally Posted by TripleW View Post
What are you gonna use to glue that back together? TW
TW, check out the repair over here. http://www.rcuniverse.com/forum/m_90...16/key_/tm.htm

Post #384, near bottom of page. After doing the wood repairs, the Gorilla glue idea sounds good. Better than filling the area with spray expandable foam, even. Doing that in the bottom area around the rear of the wing saddle area might be good idea, also. Will have to test on a piece of scrap ABS first, to make sure the GG doesn't melt it.
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Old Jun 04, 2011, 11:04 PM
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Tama, Iowa USA
Joined Dec 2007
575 Posts
Ok, here's the pics of my repair. I ended up not worrying about the upper stringers, as once the longerons were properly glued, the tail was very solid.

Hope to get to test fly it tomorrow.
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Old Jun 06, 2011, 06:11 PM
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Moorpark, Ca.
Joined Apr 2004
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Nice repairs Stagger,
I'll be sure to have a close look at mine. I've had some time to make a little progress on my TC build. I hate when life gets in the way of my hobbies Was able to finish the first nacell and get started on the second. I opted to cut the battery hatch into the side of the the nacell. I also couldn't hang with the green on the cowl so it's gone.
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Old Jun 06, 2011, 09:39 PM
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Staggerflyer's Avatar
Tama, Iowa USA
Joined Dec 2007
575 Posts
Looks good, Rick.

Welcome to the thread.

A couple suggestions, if I may. Open up the prop hub hole in your dummy motor to let mre fresh air flow thru the motor. E-Flite's are very good motors, I think, but they tend to run hot, and can quickly overheat if not cooled enough. I dropped the temp on my Power 110 in my P-6E by over twenty degrees by opening the prop hub area by 1/4" diameter from the original opening, which was about what yours is.

Don't glue your nose piece on until totally finished weighing and balancing, if you glue it at all. I used two of the extra tiny screws like used for the canopy. With your batteries mounted as they are, and the lighter weight of the .60 size motors, I'll bet you will need almost a pound of weight, +/-. The airframe and flight characteristics won't notice the weight, only you will.

Good luck, and keep posting.
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Old Jun 06, 2011, 09:56 PM
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Tama, Iowa USA
Joined Dec 2007
575 Posts
Well, I got to fly mine yesterday. Got in a great flight, and got another great video. Should have taken some photos, but I forgot.

The repairs on the rear of the longeron did wonders! Thanks for finding that, Rocketman. The tail was very solid, and pitch control was rock solid, no jerkyness. And, because we had a variable quartering crosswind in the 10-15 mph range, I had to use a lot of rudder both on takeoff and landing. My initial touchdown was not purty, quite a bounce, as it drops suddenly on full flaps if you are not on the ground. The airspeed at the point it drops is still rather high, visually. Plus, our field has always seemed to "suck" the planes out of the sky early if the wind is ~ 10 mph or more. Everyone has trouble getting good landings, no matter the plane. Below 8 mph the problem doesn't exist. I only had one good landing of my 4 planes myself, and I'm considered one of the smoothest landers in the club. Not bragging, just popular opinion. We think it's because we are in a "bowl" with only one direction level for long distance, until the corn grows up in the farm field to that direction. (South)

When I get the video posted, I will provide a link.

Here it is.
ASM Tigercat Electric (5 min 16 sec)
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Old Aug 01, 2011, 10:01 AM
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Moorpark, Ca.
Joined Apr 2004
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Hi Staggerflyer,
Got a question for you. I finished up the power systems in both nacells & have started to work on the fuselage. I also picked up the retracts & struts. My question is; did you have to cut the front gear door in half? From the limited instructions, it appears that only the front portion of the cover is used, hinged at the front & attached by the bent wires to the strut. Is the rear portion not used and a hole is left where the wheel comes down?

Rick
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Old Aug 01, 2011, 05:10 PM
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Tama, Iowa USA
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Quote:
Originally Posted by RickAvery View Post
Hi Staggerflyer,
Got a question for you. I finished up the power systems in both nacells & have started to work on the fuselage. I also picked up the retracts & struts. My question is; did you have to cut the front gear door in half? From the limited instructions, it appears that only the front portion of the cover is used, hinged at the front & attached by the bent wires to the strut. Is the rear portion not used and a hole is left where the wheel comes down?

Rick
Rick, you've got it right. The door does get cut in half. One the real aircraft, the rear half of the door double cycles, in other words, it opens to allow the gear up or down, then closes again. Much the same as the main gear doors on a P-51 Mustang.

Hint on the forward section of door. The attachments are in the fixed gear hardware, as is the cable and all it's attachments. Use the little springs to take up the slack in the cables when retracted. I bent one end to attach over the bulkhead just behind the nose wheel closed position. Have them positioned outward to keep the cables from catching on the axle as it comes back down.

Also, you may find that the wire attaching the front door to the gear is to long. Try it manually a few times before finalizing the attachment points. I ended up just leaving the wire off, as it would pop them off everytime I hit a bump on our grass runway. Air pressure keeps it closed in the air, and it rides on the "kick" point on the strut, keeping it off the wheel. Yeh, you have to hold it when picking up the fuse to move it around with gear stored for storage/transport, but hey... maybe you can figure out how to make the attachment "work" like the real one. But it has a collar on the strut that allows the strut to turn without twisting the door. There is a pic of the other F7F kit's nose gear which is more scale like, on this thread back a few pages, I think.
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Old Aug 02, 2011, 08:57 AM
Nothing Runs Like a Deere
lebus1's Avatar
Central Minnesota
Joined Jul 2008
100 Posts
Well I finally maidend my F7F on Sunday. The wind was down, the runway was widened and lengthed for the larger plane. My setup included E-Flite Power 110's, MAS 16X10 three blade prop and two 5000maH LiPo batteries per motor connected in a series. I taxied it out and tried out a bit of ground handling (settle my nerves) and then gave it full power and off we went. I used all throws by the manual. Take-off was nice and straight. I was suprised in the first turn as it needed much more control input than I'm used to putting in. I thought for a moment that this was going to be a short ugly flight as the nose was dropping without responding to the amount of input I put in. However, just by adding more input she came out of it. I adapted to the way it needs control applied and all went well. After a few circles around the field I heard a buzzing sound from the plane as it passed over. I thought it was a maxed out servo. I tried all surfaces but couldn't find it. So I wanted to get down asap instead of enjoying the flight. Trimming was just a little right aeileron and a few clicks up on the elevator. The plane seemed to fly well on bit under to 1/2 throttle. So after some quick trimming and a few passes I decided to put her on the runway. I turned onto the base leg at 1/3 power and approx 18-20% flap. I cut to just off idle to 1/4 throttle and watched it fly about 30 feet over my head. This plane likes to fly and dosn't slow down as much as other planes I have flown. The next pass I cut the throttle to zero on base and added just a bit in on final. That worked great nice touch down and rollout. I checked my servos and still could not find or reproduce the noise I heard as the plane flew overhead. I am now thinking it may have been vibration of the ABS material in the open wheelwell areas. Any thoughts on where the noise may come from? DB
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Old Aug 02, 2011, 06:31 PM
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Tama, Iowa USA
Joined Dec 2007
575 Posts
Good job on the maiden. This bird is really a pussy cat.

Did the noise go away when you slowed down, as a flutter would?? Could be motor noise, especially if ESC lost timing. But that usually happens at 3/4 to full throttle. Try setting your timing on low, and your PWM on 8K. That's what Castle recommends for that motor.
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Old Aug 02, 2011, 06:38 PM
More Combat Please!
Wind_of_Change's Avatar
Utah
Joined Dec 2003
7,840 Posts
Congrats on the maiden, lebus1.

I noticed some rattling on my ESM Pilatus when I was flying, and it drove me crazy trying to figure out what it was. Turned out to be the mechanical retracts. They aren't manufactured to the tightest tolerances and there's a little play/wobble in the struts and wheels, so they wiggled and made noise when I flew. It was annoying.

I ended up putting just a little bit of foam in the wheel well for the wheel to rest against when it was retracted, but you can't do too much of that or the resistance will keep the retract from letting the gear back down. Test it first on the ground a bunch of times, especially with your air tank partially depleted. That may be it.
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Old Aug 02, 2011, 07:10 PM
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Tama, Iowa USA
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Quote:
Originally Posted by Wind_of_Change View Post
Congrats on the maiden, lebus1.

I noticed some rattling on my ESM Pilatus when I was flying, and it drove me crazy trying to figure out what it was. Turned out to be the mechanical retracts. They aren't manufactured to the tightest tolerances and there's a little play/wobble in the struts and wheels, so they wiggled and made noise when I flew. It was annoying.

I ended up putting just a little bit of foam in the wheel well for the wheel to rest against when it was retracted, but you can't do too much of that or the resistance will keep the retract from letting the gear back down. Test it first on the ground a bunch of times, especially with your air tank partially depleted. That may be it.
Better yet, a drop of vegetable oil on the axle and all operating joints. Sure made a big difference in the operation of mine. Wish I had thought of it sooner. The metals used in the bushings is so soft they wear out in just a few cycles without oil. Mine are very sloppy, having a lot of movement that was not there originally.
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Old Aug 31, 2011, 07:32 AM
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Tama, Iowa USA
Joined Dec 2007
575 Posts
Another weak point on this model has been found. This is a big one.

Seems there is no solid wing center joint connector/strengthener. The center joint relies on just butt joining the center ribs and sheeting, plus a small piece of carbon fibre rod.

One of the guys over on the RCUniverse.com thread had his separate. Luckily got it down in one piece. Go look here to see what he found. Bottom of page.
http://www.rcuniverse.com/forum/m_90...18/key_/tm.htm

Looks like we better stay away from high G manuevers until we fix this. Gonna take some engineering.
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