Giant Scale Twins F7F Tigercat
 

Well the weather has put a damper on my ability to finish painting my Kellogg TBM Avenger, so I guess that means it's onto the next project:

I picked up an F7F Tigercat from Giant Scale Twins last summer. It is essentially a complete kit. Fiberglass fuse with vertical stab (pre-installed bulkheads), fiberglass nacelles and cowls. All the wood required to complete the airframe (formers, stock balsa, firewalls, gear mounts, leading and trailing edges and sheeting. Wings and horizontal stab are foam core and pre-cut spars are also included. There is also an extensive hardware package including the wing joiner hardware. Also nice is that each hardware pack comes with its own insert with drawings, measurements, photos and further detailed instructions on how to properly install the hardware. When I ordered my kit, Jim, the owner of Giant Scale Twins, also threw in a cockpit kit (very detailed) and dummy radial engines. Hardware is also available for the gear door mounting. I think he's running a holiday sale right now, too, so check out his website and the other planes he offers (P-51H, F-82, Aero Commander).

Anyway, the kit also comes with a very nice, easy to follow set of instructions in the form of a 38 page booklet. Lots of good reference photos that Jim took during the contruction of his own F7F, as well as drawings and a 3-view. Also, Jim highlights critical parameters and hints and tricks based on the contruction of his prototype and other follow-up F7F planes he's constructed. But perhaps most importantly, Jim provides you with his phone number and email address, and he stresses that you call or write to him if questions arise. I have already called Jim once to get some clarification before I started construction, and Jim picked up the phone right away and was happy to chat for as long as it took to answer ALL my questions. Excellent support!

Also worth mentioning is that Mike Brown and Rich Jennings did a recent review of the kit for High Flight magazine, and a video of their maiden flight is also on YouTube.
Link to video: http://www.youtube.com/watch?v=jjeYr...layer_embedded

So below are some photos of the kit contents. I also picked up the Robart gear for this model (also available through Jim), as well as some wheels.

Some specs on the plane:
1/5 scale, 116" wingspan
102" length
projected weight range: 45-55 lbs
Engines: G-62's or larger

I'm using twin DLE-111's, so that should be quite enough power!

I'm starting this the horizontal stab this weekend. Everything is layed out, and I just need to start adding epoxy.

I hope to accomplish as much as I can on the F7F this winter, but this might be a protracted project, so don't expect daily updates until the maiden! I'll do my best to keep it moving forward and keep updating the thread, though

Regards,

Noah

RE: Giant Scale Twins F7F Tigercat
 

Glad to hear you are getting it started Noah! It will be a beautiful plane, and looks like a fun project! If you need an extra set of hands over the winter, don't hesitate to call.

RE: Giant Scale Twins F7F Tigercat
 

twin DA50's will be PLENTY of power, but two twins will sound pretty cool.

Nice project!

RE: Giant Scale Twins F7F Tigercat
 

If I were not already sitting on a 50% compelted Bridi Tigercat, I would get one of these. I had the old Modair with 4.2's......WAY over powered, but with 2 blades props. Good luck with the build.
JEff

RE: Giant Scale Twins F7F Tigercat
 

"Too much engine" - you will hear. I put DA85's in my 114" P-38 and the voices came up...:D

DLe 111 it looks like you have enough room for these twins...keep the pictures rolling.

RE: Giant Scale Twins F7F Tigercat
 

The help I need, Chad, can only come in the form of you breaking-in and vetting these motors on one of your 35% aerobatic planes!

I am planning to use (less-efficient) 3-blade props... lot's of room between the nacelles and the nose for a couple of larger diameter screws.

Noah

RE: Giant Scale Twins F7F Tigercat
 

haha, nothing wrong with too much, thats why they have throttles ;) Ive seen a 120" P38 fly recently with two da50's and it was off the ground in 20' :)

RE: Giant Scale Twins F7F Tigercat
 

Hey Noah,
Does this mean you won't be buying anymore of my Warbirds?? LOL Anyway, I'll be watching the build. I'm sure if anybody can do it justice , you can.
Thanks,
Fred Menna Check6

RE: Giant Scale Twins F7F Tigercat
 

Hi, Fred.

I still keep my eyes peeled for your ads!

But honestly, yes, I've become attached to building and the models that really peak my interest are not often (or ever) bought and sold.

Have a good Holiday, Fred.

Regards,

Noah

RE: Giant Scale Twins F7F Tigercat
 

I have one as well. I will be putting 3W 106s in mine, simply because I have them.

RE: Giant Scale Twins F7F Tigercat
 

Hey, Jeff.

Please feel free to contribute to this thread. Any and all information is welcome!

How far along are you on the build?

Noah

RE: Giant Scale Twins F7F Tigercat
 

I see Darrell is lurking....

Don't worry, Darrell... I'll be getting replacement gear from you as soon as the aforementioned gear prove worthless!:D

Gads, I just used a smiley... first Robart gear, now a smiley... what next?!?!

Noah

RE: Giant Scale Twins F7F Tigercat
 

Well, it's official.

The project F7F is underway.

As I indicated above, I started with the stab. Very simple contruction.

First step was to epoxy the left and right stab cores together, being very careful to maintain straight trailing edge/aligned leading edges. Once the core was set, the 1/4 ply spar was epoxied into place. After that, the leading and trailing edge balsa was epoxied to the cores, followed by tip blocks.

After dinner tonight I'll rough-sand the leading and trailing edges and tips to shape, then run the stab through a bandsaw (with fence) to cut away the elevators. Keeping the stab in the lower shucks will help ensure that I get a nice vertical cut with the saw. After that I can add balsa to those exposed edges of the core, rough-sand the balsa and then sheet the stab. The sheeting is 1/64th ply (both wing and stab).

I serisouly believe that the longest part of this build will be waiting for the epoxy to set so I can move onto the next step. Everything has been perfect so far.

Be back soon with a finished stab in hand.

Noah

RE: Giant Scale Twins F7F Tigercat
 

Noah,

Not lurking, just checking out what is being built with competitors retracts.
Most of them seem to be first timers or die hard Ford vs. Chevy builders.

Nice start though.

Darrell

RE: Giant Scale Twins F7F Tigercat
 

I purchased Jeff's Modair F-7-F a few years back. This thread may give me the motivation to get it airworthy again.

RE: Giant Scale Twins F7F Tigercat
 

KP, please also feel free to contribute to the thread and share pictures and your experiences. My interpretation of what you wrote is that you had a mishap with the finished model. Is that correct?

Darrell, no offence was intended when I said you were lurking. I understand your motives for checking out these projects. When I get closer to an all up weight, I'll have a better feel for whether the Robarts will hold up. Several of these Giant Scale Twin models have been fitted with the Robarts, including Jim's ~80 lb twin-radial version pictured on his website, so they may be just fine in the end (but I of course will contact you should I not feel comfortable with these gear).

Anyway, back to the task at hand.

After the blocks and edges were epoxied into place, the wood was rough sanded. Easy work with part in the shucks, some 80 grit paper on a sanding bar and some tape to protect the foam.

Next the stab was placed back into the top and bottom shucks, and taped up so the assembly would not shift about when the part was passed through the bandsaw. Before cutting, both the shucks, stab and elevators were all labeled top, bottom left and right so that when it comes time to sheet, all the parts find their shuck-mates without guesswork.

The elevator was cut away from the stab, and then another pass was made to remove an additonal 1/2 inch from the elevator side. Measurements come from the measured drawings in the back of the provided instruction manual. The 1/2 of removed material will be filled with 1/4 balsa attached to both the new stab trailing edge and the new elevator leading edge.

After the new edges are added, making sure the stab and elevator are kept absolutely straight, the new wood will be rough sanded and then the parts will be ready for sheeting. Should not be too much trouble to get it all done today.

Then it's onto the main wing cores.

Back soon with more updates.

Noah

RE: Giant Scale Twins F7F Tigercat
 

Noah, the Modair I sold to KP (Rick) splatted as a result of losing one elvator servo. I got it back down in one piece, but it hit hard, bounce and rolled on its back. I flew it inverted into the ground leaving about a 50 foot gouge in the earth from the vertical.

Jeff

RE: Giant Scale Twins F7F Tigercat
 

Ahhh... too bad about Rick's model.

Speaking of losing elevators... I was a little worried about only having a 1/4 balsa trailing edge to secure the Robart hinge-points. The hinges would pass right through this 1/4 balsa and mostly be glued to the foam core. I deviated from the plans here and installed some balsa hinge blocks along the length of the stab and the elevators. I used really light balsa that I found at a craft store recently, and I used very little epoxy to hold the blocks into the foam (the sheeting will essentially lock the blocks firmly within the stab or elevator), so this modification should not have added too much additional weight.

Started by marking the hinge locations, then used a soldering iron and copper wire to melt out the cores for the balsa blocks. Oversized blocks were then epoxied into place, then flush cut and sanded to match the surface of the foam (lots of tape to protect the foam here).

Once those were in place, it was onto installing the stab trailing edge and the elevator leading edge.

With all that out of the way, I'll sheet the stab and elevator tonight after dinner.

Noah

RE: Giant Scale Twins F7F Tigercat
 

butlern,

Looks like you are off and runnung. You will most likely be flying before I get my B-25 parts cut, so please keep the thread as a F7F only.
Looks as if you have a following. Thanks for the tip on the F-82. I am going to check out the web-site and maybe put one in my shop for the future, the distant future.

Hope you do not mind me putting in this plug for my upcoming war bird fly-in.

Everyone, You are invited to my 2010 WARBIRDS OVER OKLAHOMA 2010 Fly-in on May 14-16.
Please visit our web-site at www.warbirdsoverok.org



Thanks, Flight Leader

AKA: WARBIRDRCER

RE: Giant Scale Twins F7F Tigercat
 

So a little more work done on the F7F, but not as much as I hoped due to the holiday.

I finished the stab and elevators, fully sheeted and ready for fitting to the fuse and then fiberglass, so I moved on to the main wing sections.

Started with the center sections. Wrapped the leading and trailing edges in balsa, then use a razor plane followed by 80 grit paper to rough sand them to match the airfoil contours (ready to accept the sheeting). I also added some of 3/32 balsa strips that cover the servo wire tunnels, and installed the upper and lower hardwood spars (1/2 x1/4).

With the center sections wrapped in balsa, I did the same with the outer wing panels, and added the wing tips, too. The balsa on the outer panels has been razor planed and rough sanded, too (except the right wing tip balsa block). Shaping the leading, trailing and wing tips generated two full garbage bags of shavings. What a mess. As you can see in the photos, I don't have a work shop, just a downstairs family room, so I have to clean up regularly before my wife see what really goes on downstairs!

I also made up the wing joiners. These will be set into the inner and outer panels once all the spars are in place. Alignment will be verified with the cores weighted down on the bottom shucks. Once alignment is OK, they will be epoxied into the wings.

The next step will be to layout the firewalls and dry-fit the nacelles. With the nacelles in place, I can then trace their outline on the bottom of the inner wing panels. Once those I are drawn, I can then mark the cutouts for the flaps, as well as layout and cut the foam for servos mounts. When I get all that done, I can cut cut the flaps, wrap the trailing edges with balsa and then get the wing sheeted.

It's still moving along fast, I have only spent three afternoons working on the kit so far, and the wing is already taking shape. I'm starting to like working with foam core wings!

Be in touch again soon.

Noah

RE: Giant Scale Twins F7F Tigercat
 

Thanks for the update. I see what you mean about the shavings. I did look at the F-82 and what a nice looking plane. I would guess the construction would be a lot like your F7F.
Looking at the last photo, do the outer wing panels come apart?

RE: Giant Scale Twins F7F Tigercat
 

Hey, Steve.

Yes, the outer panels come off, just outside of the engine nacelles. Those joiners shown in the picture above keep the outer panels tightly connected to the center section. Two joiners per side (front and rear). The ply plates get epoxied into the wing foam, and the plates also get epoxied to the hardwood spars. Nice and strong. The inner panels will be joined togteher permanently to form a single center section.

I think you're correct, the F-82 contruction would be very much like this F7F. Pretty fast going. As I mentioned last week, most of my time has been spent waiting for epoxy to cure.

Regards,

Noah

RE: Giant Scale Twins F7F Tigercat
 

butlern,

Just discovered a friend has the same F7F you are building. I knew he had a giant F7F, but was told it was the same kit.
I will see if I can get you a video of it flying. Well as soon as the temps get above freezing.

Happy New Year

RE: Giant Scale Twins F7F Tigercat
 

Hi Noah,

I'm the new onwer of the F7F tiger cat that ws built for the High Fligh Mag article. I have went through this aircraft and can't wait to fly it. I went and visited Jim as his Giant Scale twins shop, Came home with a new P-51h.

Anyway like the thread and will be watching. If you need any input let me know. Thw twin zenoah 80-t that I have my f7f are more than enough. If you have not thought it purchase the ring of fire exhaust. makes the aircraft purr like a real kitty Kat.


keep me posted.


Laudy "LIMO" Jim

RE: Giant Scale Twins F7F Tigercat
 

Hey, Jim.

Congratulations on the new tigercat! I'm looking forward to hearing about your experiences flying the model. Nearly everyday I visit the website that Rich Jennings put up with all the pictures that they took during the contruction of your plane. Looking forward to communicating with you more about the Tigercat.

I know the 111cc engines are overkill, but they certainly do the job and I can always throttle back (and I'll be running less-efficient 3-blade props).

By the way, did those guys put brakes on your cat? I thinking about getting a brake set for this (which would also require new wheels, unfortunately).

Anyway, I had an opportunity to spend a few hours on my model this weekend.

I finally got around to mounting the firewalls (temporarily) so that I could dry-fit the nacelles and trace their outlines in the bottom of the wing. The firewalls are first fitted with a couple of balsa ribs/spacers that position them correctly on the wing. Once set in place, their outlines were marked in the leading edge. A dremel with router bit was used to create the 3/8" recess in the leading edge. Once all was right, the firewalls were screwed to the leading edge. I used 3 long drywall screws for each part, and positioned them so that the holes could later be drilled-out for the 3 hardwood dowels that effectively pin the walls to the wing leading edge.

Once the firewalls were secure, I got the nacelles into position and traced their outlines on the bottom of the wing. This helps map out all the control surfaces, and this is particularly critical to ensure the flaps are sized, positioned, and eventually cut out of the wing correctly.

So after the nacelle lines were drawn, I used the sketches in the instruction manual to mark out the position of the ailerons and all flap sections. I also marked the position of servo bays and the hardwood braces that will support the servos. The servos will be mounted to 3/32 aircraft plywood plates. The ply plates will be screwed to the hardwood braces mounted in the wing. I made a card stock template to trace onto the wing so I knew where to cut out the foam to install the braces. Anyway, in order to get the top of the servo plate flush with the 1/64th sheeting that goes over the foam, I also had to take the dremel and router out each of the hardwood braces. The outer flap servos are going to be done a little differently, for a number of reasons, so I'll describe the installation of those sometime down the road.