Fun Fighters

[Strix]

This is awesome, Nic! I'm finding myself really attracted to the funfighter-sized models, for a number of reasons. Smaller models are cheaper to build and they fit in my car better. Plus I live in an apartment, so space there is limited as well. And all my flying buddies keep tending towards bigger and noisier models, and I like to be contrary, so I'll go smaller and quieter.

I watched you fly that prototype, and I was absolutely amazed at how quiet that little P-39 was, for the speeds it was going. It was something else! Now I can't wait to build one and make all my ARF-flying buddies jealous.

 

[herk1]

I should have posted this earlier, but Atomik RC has been closing out the funfighter airframes at very good prices. I snagged five different models! Unfortunately most of the models have sold out just in the last day or two, but they still have one of the models featured in the Flitetest "funfighter" episode that this thread is about (see post #1 of this thread): the A-1 Skyraider. And they also still have one of the relatively new models - the Grob. I got one of the last Spitfire airframes with my order today for only $11.99! At that price, it's not worth the trouble of downscaling the FT-Spitfire to 65% for a DTFB-equivalent "funfighter" airframe.

http://www.atomikrc.com/collections/rc-airplane-parts/skyangel

(scroll down)

 

[Joker 53150]

Good call! My F-4 Corsair is a blast to fly, but landing it gives me a 50-50 chance at damage. The gull wing design puts two small sections of the wing as the lowest points on the plane, and they grab the ground which results in a violent spin. I've broken the fuselage in half 3 times and the wing once. I'd like to blame my flying style, but I'm pretty conservative overall.

I ordered the P-40 and Spitfire so I have a body once the Corsair is no longer repairable.

Now I just need to see what it'll take to give the P-40 a good paint job. The colors are HORRIBLE!

 

[herk1]

Yes I decided early on with the Corsair that I would land it on pavement not grass, because of the way it catches in the turf and violently jerks around or flips over. I taped up the wing "elbows" so that paint and foam wouldn't be scraped off when skidding down the runway. I've never broken a prop with it by landing on pavement, because of the way I kill the power pretty far out and glide in. I've done that enough times that I can calculate the glide well enough to drop it in practically at my feet.

Were the P-40 and Spitfire indicating in-stock status when you ordered them? Because they were showing "On Backorder" earlier today. And since they are being discontinued, I wouldn't think that they would have gotten any more in. Like I said, it was showing just the A-1 and Grob left. Maybe they discovered some other leftovers in the warehouse or something that weren't in the computer inventory?

 

[Joker 53150]

Their system let me order both of them, but now they show as out of stock again. I did get the confirmation on the order, so I assume everything went OK on the order. Now when you look at them and try to order it directs you to Amazon where these airframes are much more expensive.

One thing I should have done was to order the pushrods with the airframes. Making my own is easy, but it's so much quicker using pre-made.

 

[Joker 53150]

My planes showed up today! The box for the Spitfire was damaged quite a bit, but the contents were in good shape. The fit and finish on the P-40 is much better for some reason. The wing tips on the Spitfire droop down, so I'll need to get that fixed up before flight. The canopy is a much tighter fit and the magnets aren't as good either. Strange quality control....! Also, the P-40 included the control horns pre-installed, came with the pushrods, and a spinner & prop, none of which came with the Spitfire. I didn't expect any of it so it was a pleasant surprise.

Here's my growing fleet of tiny warriors! I'll need to make some vinyl decals at work for the new additions, they look naked without. It's hard to tell on the Corsair, but she's taken a lot of abuse from landing on the gull wings. A broken wing and multiple breaks on the fuselage. If/when it is no longer airworthy I've got candidates to use the electronics on. Unless I don't get the motors, ESCs, and servos and just make them ALL flyable...!

 

[earthsciteach]

Dang! I totally missed this. Just went on that site and they seem to only have boats and land vehicles.

 

[Joker 53150]

Yeah, I'm not sure how these planes fit into their regular product mix, unless they just got a big batch of left over parts cheap and blew them out for a quick buck...? They do have one frame left, as of yesterday. It's a strange looking plane and I couldn't bring myself to order it when I got these.

The Corsair has been fun to take to the field my dad flys at. Dad is the only "electric only" guy there, and most are flying only nitro. They'd fly doing their high-speed passes, and then I'd break out this little (by comparison) Corsair which one guy said was "cute". With the 4S high-discharge battery it was probably the fastest plane at the field, and got their attention! I still would love to get a radar gun to see how fast it really goes.

 

[AkimboGlueGuns]

The A-1 is still available from HK. I'm not sure how much longer that's going to last, but you can still buy a RTF fun fighter.

 

[herk1]

Joker53150 - My second batch of bargain airframes (two this time, for a total of five) showed up on the same day as yours (yesterday). Of my five (Wildcat, Skyraider, Grob, Spitfire, FW-190), only the Grob came with the control linkage hardware and prop/spinner (as well as two identical-twin pilot figures in the cockpit!). The other four had only the foam, canopy, and cowl. I've been putting together the Grob (that "strange-looking" plane ).

If your magnets don't seem to be catching, check them for reversal. On my Grob, one magnet was reversed...it was repelling the opposing magnet rather than attracting it! The hatch was more than just a tight fit -- it wouldn't go fully into the cowl at all. So I sanded down the top/front part of the hatch that slides under the cowl, being careful not to take away too much. I sure don't want it loose...because I don't trust those magnets to hold it in place. I had a problem with my second Corsair with the hatch sliding forward in flight enough for the catch at the back to come out.

Unfortunately, with the Skyangel planes, warped parts are more common than not. On my Sea Fury funfighter, the wings arrived severely upcurled literally to the extent of a Parkzone Radian! Fortunately, on small planes like these it's pretty easy to straighten out warped parts with a hairdryer on high heat and a little gentle/steady bending/pressure. Heat it up, then hold it in place till it cools. Don't use a heat gun -- that's too hot -- I tried that once and it caused instant "alligator skin" puffing.

The Grob is the only one of these funfighters I've seen that is designed with an optional 4th channel in mind. The rudder isn't hinged, but it has the cutout line well incised, and there are pushrod channels on both sides of the aft fuse (one for elevator, one for rudder), and the aft fuse servo pocket has room for two opposing servos. I'm definitely going to add/hinge the rudder. At the speed this thing will go, and the size of the rudder, I expect knife edges to be possible. I installed a Cobra motor in it that is almost exactly the same size and Kv as the funfighter motor, but much better quality (link).

 

[Joker 53150]

I guess I got lucky with the P-40, as there is nothing warped I could find. The Spitfire is minimal, with only the wingtips warped down a little. The Corsair's elevator had some warp, but not too bad.

It looks like the magnets in the P-40 are good, but the Spitfire certainly could use a little bigger magnets to hold that canopy in place. With the Corsair I had problems with the entire tail section flexing down at high-speed, causing it to dive. Not a good feeling as you're doing a high-speed low pass!! I added two magnets at the rear of the canopy and that fixed the issue.

Once Spring is approaching I'll need to invest in a bunch of 4S batteries. Flying it only once at high speed is no fun! The 3S I have are amusing and it moves well with them, but that extra voltage really makes it fun.

Maybe I'll have to order a Grob, just for the fun of it. Electronics for these things are pretty cheap, after all. Are you doing anything special with the ailerons, or just running a Y harness? To try and slow the Corsair down I ran the ailerons each on their own channel so I could do flapperons. I haven't played around with them enough yet to know if they really help, but anything that slows it down for landing is helpful!

 

[herk1]

Actually, compared to the floatier, lower-drag Rare Bear, P-39 (which I no longer have), and Sea Fury, the much draggier Corsair slows down quickly with the power off, so no I haven't tried anything to change it, and I just use the Y-harness. The slick Rare Bear definitely is more of a challenge, requiring that I sail her out much farther on downwind, to make for a long power-off final glide-in (I wouldn't try flaperons on the Rare Bear because it already has a bit of a tip-stall tendency as-is). But I have a long club runway to land on, so there's plenty of margin for error. I taped a section of 2-liter soda bottle onto the belly of the Rare Bear to protect it, and two small plywood landing skids on the Sea Fury.

 

[herk1]

The A-1 is still available from HK. I'm not sure how much longer that's going to last, but you can still buy a RTF fun fighter.

The problem with the electronics-included funfighters from HobbyKing is that the gear they come with is either so-so (servos and motor) or terrible (ESC). And the price is just too much, for what it is. The prices on the HK funfighters at USA-East warehouse (after the discount for "Platinum member"...or just wait for the offer) range from $68.73 (Corsair) to $84.99 (Spitfire) to $98.58 (Rare Bear), etc. (others in-between).

The biggest problem with the gear that HK puts in the funfighters is the ESC. It is allegedly a "20A High-Spec 3~4S" ESC. But it's huge, and heavy, for a 20A ESC. It weighs 34 grams. That is heavy even for a 30A ESC, to say nothing of a 20A! (For example, the 30A, 4S-capable ESC shown in the photo I just posted of my Grob is this one: http://www.hobbyking.com/hobbyking/store/__70237__Hobby_King_30A_ESC_3A_UBEC_AR_Warehouse_.html , which weighs 32g.) What really takes the cake is that anybody with a wattmeter can see that the supplied funfighter motor pulls well over 20 amps on 4S. So HK's claim that you can just drop in one of their special funfighter-size high-C-rating 4S LiPos and go fly is problematic. Sooner or later, this is the likely result:

https://www.youtube.com/watch?v=84GK3Ll8On8

(go to about 11:40 in that video)

Note that the ESC Bruce recommends as a safe substitute for the supplied one is the same one I linked to that I am putting in my Grob.

So it's much better to just get a reasonably-priced airframe (if and when you can find one!), then equip it with better, but still modestly-priced gear. For example, the Spitfire airframe ($11.99) plus that blue ESC ($10.76), three HXT900 servos ($8.97), and for a motor, there's a variety of choices for about eleven bucks, including HK's own alleged "funfighter replacement" motor (or preferably a better motor, like this one: http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=12919 ). So that's a total of about $42.72. Which is nearly half of HK's price of $84.99 for their PNF version. Of course, it doesn't have decals or control linkages. But on the other hand, the components are better ones of your own choosing, and you avoid that dreadful ESC (of which I have a whole pile of them that I will probably never use, sitting in a spare-parts bin).

 

[Joker 53150]

Curse you! I just pulled the trigger on a Grob as well. For the price it's hard to beat, and I'll have one more pocket-rocket available for the electronics from the Corsair.

 

[herk1]

No, curse you for snagging the last Grob! I think I'm gonna really like this thing and will probably regret not getting a backup airframe while they were hot. The few flight reports I've seen of it have all been very positive. I just finished the build, including the rudder mod. Balanced perfectly with the 1000 mAh 4S LiPo right over the wing. (going 4S right from the start!)

 

[earthsciteach]

Ooo! The Grob is pretty!

 

[Joker 53150]

My timing is pretty good then, as it looks like I got the last P-40, the last Spitfire, and maybe the last Grob as well!

The 4S 850mAh fits and balances perfectly in the Corsair, and looks like it would be good in the Spit and P-40, so I'll probably order a few as Spring rolls around. 3-1/2 minute flights are over quickly, but my heart and eyesight can't take much more than that.

Post a flight report on the Grob when you can, please!

 

[herk1]

I maidened the Grob "funfighter" this morning. "Two thumbs up" on this one! I put four LiPos through it -- two 4S/1000 and two 4S/850. It's actually a pretty easy, relaxing plane when you keep the speed down. The red paint accents I put on the upper wings and stab were a big help with orientation (plus, the bigger wingspan compared to other funfighters helps with that too). Hand-launches were no problem -- I just gave it the "standard funfighter launch" -- i.e., an underhand shove at about two-thirds power and a rather steep "up" angle -- and she pulls right into the sky just like most of the other funfighters. It helps if you don't have small hands on this one, so you can get a grip on the "double-wide" cockpit over the CG.

The top speed was faster than the Corsair, but not as fast as the Rare Bear (the consensus is that none of the other funfighters is as fast as the Rare Bear). With the funfighter-size 5.5x4.5 prop that I used, the Cobra motor got only a little warm. The battery and ESC a good bit more warm though. Unfortunately there is no air ventilation for the equipment compartment -- entry or exit. I might punch some holes 'somewhere' for that.

The Grob with the rudder added is definitely more aerobatic than any other funfighter. Sure enough, it will do knife-edges! -- and quite easily. I also did some snap-rolls, and it snaps in the blink of an eye...in fact so quick I was worried about overstressing something (and that was only doing it at medium speed, not high speed). Inverted flight feels about the same as with the Sea Fury -- i.e. just a little elevator (compared to a lot of elevator with the Corsair), and reasonably stable.

I did all landings in the grass. It was pretty well-behaved for that -- especially compared to the Corsair. I had daubed some epoxy on the three lowest points of ground contact (the twin exhausts and the dorsal fin) for some extra durability.

 

[Joker 53150]

Nice flight report, and nice subtle paintjob! This plane is how I like 'em, a blank white canvas! I might have to get a little creative with mine in the near future.

 

[herk1]

I did some windy-day flying today with a bunch of my faster planes that handle wind well...including the new Grob. It was so windy that while I was flying one plane, my Rare Bear got blown off the setup table (fortunately no damage...that thing is tough!). While prepping the Grob for it's fourth flight, it occured to me that I hadn't checked the motor mount for security. Sure enough, the darn thing was loose.

When the funfighters first came out, lots and lots of people (including me) discovered that their motor mounts would dislodge easily due to being inadequately glued at the factory. All it would take would be one noseover to make the motor like a loose tooth (if it wasn't that way from the start). Then after several months it seemed like J-Power responded to the complaints and suddenly the newer funfighters started showing up with heavily-glued motor mounts.

Well my Grob airframe is like the earlier ones. When I got home I pulled out the motor mount completely, and it came off easily. There was hardly any glue on it at all. Of the three arms where the motor attaches to the foam, only one had a small dab of glue, and the other two maybe just a speck...virtually none. So I epoxied the snot out of it. While I had the cowl off, I cut some room in it for air to come in, and cut an air outlet just in front of the dorsal fin. Speaking of the cowl: that's another thing with these planes...never glue the cowl on. Or you might have to rip up the front of the plane to get it off, if and when you have a motor mount issue or something. I just tape the cowl on with packing tape at three points: left, right, and bottom. Then when I need to get it off I can either pull off the tape or slit thru it with a hobby knife.