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Old Dec 30, 2010, 06:44 PM
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Tama, Iowa USA
Joined Dec 2007
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Build Log
ASM F7F Tigercat

Hi all, decided to start a build log on the ASM F7F Tigercat, since I can't find one here on the RCGroups.

At 82" wingspan, it's a good sized bird.
Wing Area: 1160 sq inches
Length: 72"
Ready to fly with retracts (air, custom, with working oleo struts) is supposed to be approx 17lbs, but those I can find have been coming out around 19.5-22lbs.
Wing loading listed as 30-34 oz/sq ft. At reported weights, it comes out to 38.7-43.7 oz/sq ft. (The ESM kit builds much heavier, and still flies well.)

I will be using 2 Scorpion 4025-12 motors with 2 Castle Phoenix ICE 100 ESCs, turning either Master Airscrew 16x10x3 or APC 15.75x13x3 props. The prop used will determine the batteries. MA props will use 6 cells, 5000mah Blue Lipos, the APC props will use 5 cell, 5000mah Blue Lipos. Flight tests will determine final full time use. ( I already have the batteries, and use the power system in my Black Horse P-40C Warhawk. Very happy with the performance.)

Here's a pic of pieces as removed from box, and then quickly slipped together. It's BIG.

Going to take a while to complete. Retracts should get here either before weekend, (tomorrow,) or first of next week. Still have to order power systems. Because of work, I can only work on it on weekends, once holidays are over.
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Last edited by Staggerflyer; Dec 30, 2010 at 06:45 PM. Reason: spelling
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Old Dec 30, 2010, 06:59 PM
Dream Build Fly Scale
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Philadelphia, PA
Joined Oct 2004
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Nice project, looking fwd to this one. Would be neat to find props to spin in opposite direction. Would eliminate any torque issues on take off.
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Old Dec 30, 2010, 08:25 PM
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Tama, Iowa USA
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You found this one already, SS. Great.

I don't think there will be that much, not as much as the Staggerwing has, that's for sure. This one has a big rudder, and a nose gear anyway, which helps.

The real Tigercat did not use counter props. I'm thinking of putting about 2 degrees outside thrust on each motor. That should help counter it. If I can come up with a way to setup a shut-off for individual motors, it would work for engine out operation, too.
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Old Dec 30, 2010, 08:39 PM
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San Diego, California, United States
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Cool project. I have one of these I'm hoping to get started soon. I'm just waiting on motors and 1 more ESC to show up. My dad flew the first one of these that was in country and liked it alot. It's a beautiful airplane.

Based on what he said, the airplane didn't really have any torque issues really, it's rock solid on the ground and in the air. Also, based on the gear height, the largest prop you can get on there is realistically 15". If I remember correctly, I think that gives about 1" prop clearance. He wanted to run 16" but couldn't because prop clearance was an issue.



Chris
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Old Dec 30, 2010, 10:14 PM
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Tama, Iowa USA
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Quote:
Originally Posted by JetMang View Post
Based on what he said, the airplane didn't really have any torque issues really, it's rock solid on the ground and in the air. Also, based on the gear height, the largest prop you can get on there is realistically 15". If I remember correctly, I think that gives about 1" prop clearance. He wanted to run 16" but couldn't because prop clearance was an issue.
Chris
Oooh. Hope not. Will have to see once I get her on her gear. Since most of the fields I will fly her at, all have petromat runways, hopefully there will be plenty of clearance. 15 inch 3 blades in 10 -12 inch pitch are hard to find.
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Old Dec 31, 2010, 09:21 AM
Dream Build Fly Scale
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Philadelphia, PA
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Quote:
Originally Posted by Staggerflyer View Post
You found this one already, SS. Great.

I don't think there will be that much, not as much as the Staggerwing has, that's for sure. This one has a big rudder, and a nose gear anyway, which helps.

The real Tigercat did not use counter props. I'm thinking of putting about 2 degrees outside thrust on each motor. That should help counter it. If I can come up with a way to setup a shut-off for individual motors, it would work for engine out operation, too.
I didn't realize that about the full size tigercat. I was just thinking with the motors so far out on the wing that it would create quite a turning moment about the center.

Chris, good to see you in this forum too. Stagger you're in competant company with Chris following along.

I'm curious about large electric twins for thier reliability. A couple years ago I started working on a 100" DH Sea Hornet for twin 2C motors (one clock wise, one counter clock wise), but put it on hold as the 2C reliability always maybe me hesitant. I'm thinking about getting back to it with a pair of Hacker A60 motors. We'll see.
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Old Dec 31, 2010, 10:30 AM
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Tama, Iowa USA
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The reliability of the systems is much higher than even a few years ago, so... Go for it.

For bigger models I would suggest using separate power systems, just "Y"ing the throttle control from the reciever. Also, use a separate flight pack power system. Other than that...

I wouldn't be surprised if I have flown with Chris, or maybe his Dad. I see he's from San Diego, where I'm from, also. (I moved to Iowa in 1975, then moved back to San Diego from 1988-1995.) I belonged to the club that flew at the old landfill just west of College Grove Mall, along/above Interstate 94. I also flew out at the Lakeside club field, which was next to the old El Capitan High School practice football field. My dad and I used to fly at the field down in the riverbed by El Cap, also. Oh, and I also flew a couple times at the Miramar Naval Air Station's club field northeast of the runway approach. I lived in El Cajon. Grew up in Santee.
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Old Dec 31, 2010, 10:42 AM
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Tama, Iowa USA
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Working on putting the tail on the fuse now. Wings are pretty much done. Just need to drill and install screws in the outer wing panel spar tubes. I'm going to install wood dowels into the tubes to give the screws something solid to screw into. Since I have a small SUV, 2004 Ford Explorer, and only have large aircraft .60 size and up, (5) this one will be broken down every trip. (I know, I need a trailer!)

I'm finding the instructions are very basic, and the kit has been finalized long after the original instructions were printed. The control linkages are totally different than the instructions show, and items are not finished the way shown. There are also some extra ABS trim parts not covered in the instructions. An experienced modeler should have no trouble building this model, as the instructions do give the basics necessary, but not much more.

Well, have to take the wife to work, (bad weather,) will post more later.

Don
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Old Dec 31, 2010, 11:46 AM
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@ Staggerflyer, I hear you on the props. I've ultimately decided to select my power system around an APC 15.75x13 3-blade prop that I'll cut down to 15". Not the most scale looking prop per say, but there's a real limited selection on 3blade props in this size and you're lucky if they have a larger than 10 pitch. I'm not sure we've had the opportunity to fly together unless you ever came up to mile square park to fly in those years you were in SD? I grew up in the LA area and then moved to SD for work in 2003. I currently fly at the miramar site.

@ SS, I can back what staggerflyer is saying regarding twins. My F-14 twin EDF I was flying some 5 or more years ago I had setup running twin ESCs through a y-chord into the Rx. I also ran separate battery packs for each fan. I've found this really works well and plan to setup my tigercat (and any other twins for that matter) exactly the same. I don't think you'll have anything to worry about with your Sea Hornet, especially if you go with a pair of A60 motors...so long as you don't push things too hard obviously. You know, my first two flights on that tomcat were with big ol' gp-3300 nimh packs. it was shortly thereafter that thunderpower came online with their first lipo offerings. Things sure have changed since then!


Chris
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Old Dec 31, 2010, 03:36 PM
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Newcastle, New South Wales, Australia
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Don,
Did you see the article on the electric conversion of one of these in an English RC magazine early last year?

Regards
Peter
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Old Dec 31, 2010, 10:31 PM
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Tama, Iowa USA
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Quote:
Originally Posted by Peter M View Post
Don,
Did you see the article on the electric conversion of one of these in an English RC magazine early last year?

Regards
Peter
No, I didn't. I know there's probably more than just a couple out there flying, but there is no build log here for one, so I thought I'd do one for those still thinking about getting it. Much like all the other build logs on the different forums. I've learned a lot for my other builds from the logs done on them.

And if anyone wants to join in, or has some ideas/tips from one they have built, or know about, by all means, join in. I sure don't know everything, even tho' I've been building & flying R/C since 1981, and U-Control since, maybe 1960, could even be a little earlier. I just got into electrics about 5 years ago, and have been switching over to 100% electric for about 3 years. This will be my third twin, second electric. My first twin was a combining of two Fun Sport P-51 Mustangs into a P/F-82 Twin Mustang, powered by 2 HB .25s, built in the early '80s. Was a good flyer, and I did have a couple engine out events, all ending well. My second twin was the E-Flite P-38, with two E-Flite 450s. It met it's demise last New Years day Freeze Fly when we tried to hand launch it in high winds (about 15 mph+) and the launcher hit his hood on his jacket with the wingtip. Could not save it...

So, follow along, or join in, all welcome.
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Old Dec 31, 2010, 11:42 PM
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Will be watching this with great intrest as Santa, aka, the wife, had one of these under the tree, well, not really under the tree (much to large a box), but close enough. I still have to finish a H9 P-40, 90% complete, before beginning the Tigercat. I can vouch for the effectiveness of the APC 15.75" X 13" 3 blade prop cut down to 15". I've done that mod on my H9 Spitfire with fine results. 1300+ watts with an e-flite 60 and 6s 5000 lipo. 15 X 8s just didn't get the job done. So you're figuring 20+ lbs. Sounds like 1100 to 1200 watts per side to fly scale like. maybe 2 e-flite 60s & CC 80 amp ESCs on 2 6s 5000 batts?? Good luck! Happy new Year!!

Rick
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Old Dec 31, 2010, 11:50 PM
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Tama, Iowa USA
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My retracts arrived today, but I didn't get any work done on her. Had to take the wife to work, about 20 miles away, during an ice storm. It was bad enough I decided to stay in the town where she works, which is also where the club I fly with is located. Marshalltown, Iowa. So I spent the day at one of our members house, who lives close to where the wife works.

Maybe tomorrow.
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Old Jan 01, 2011, 12:10 AM
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Tama, Iowa USA
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Rick, welcome. I have the Black Horse P-40 from Hobby People, with the Scorpion 4025-12, 440kv, motor with Castle Phoenix ICE 100 ESC, turning the APC 15.75x13x3 prop at full size, using 5s 5000mah 20C Blue Lipos. 65.3" wingspan, flaps and mechanical retracts, 9lb 2oz auw. 84.7 amps, 1585 watts. This is the same power system I am planning on using on my Tigercat. Should pull it with authority. It pulls the P-40 straight up till I back off.

I'm basing the 20lb weight on reports from other sites. These were/are nitro powered planes, I haven't found a weight report on an electrified one, yet. All of my electrics have come out slightly lighter than the same models with nitro, and dry tanks. So...

Don
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Old Jan 01, 2011, 11:32 PM
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Don,
I've been interested in these for a while and nearly bought a NIB ESM version last September. If it wasn't for the fact I was off to the States a few day later, I would have bought it!

Anyway the one that appeared in RCM&E in December 2009 and January 2010 ran E-flite Power 60's spinning APC-e 14x10 props and powered by two 6s 3800's. It appears the author was quite happy with it but suggested to throw away the undercarriage doors!

Good luck with it! I might just buy one myself!

Regards
Peter
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