I stopped by my LHS the other day, and was delighted to see that Dennis had one of the Wildcat ‘Airframe Only’ kits in stock.  It was only $79.99, and building my Mustang was so much fun that I just could not resist. 

I used the typical electronics shopping list:  Turnigy 3536C-1100, Turnigy Plush 40, Rhino 1350 30C lipo, Master Airscrew 10×8 prop, and 4 HXT900 micro servos.  I decided to fly it FM, mostly because I can buy nice R790 receivers for cheap on Ebay, and I had one on hand.

The next thing I did was get ahold of Gary at CustomRC to see if he had plans to do an aluminum mount for the Wildcat.  He does plan to make one, but since the plane is brand new it was going to take a few weeks before he was ready to ship one out.  I knew I wanted to use the same Turnigy 3536-1100kv motor I had used in the Mustang, so, I decided to make up a little mount adapter to compensate for the fact that the Turnigy is shorter than the stock PZ 480.  I used some .125″ aluminum plate (measured  3.14mm) and some 1/2″ aluminum standoffs.  I’m not that great at layout, but I got the job done.  Thank God for the drill press.

This is a really cool foamy.  The thing is loaded with neat features, like a rigid battery box that will take 1300 or 2100 batteries.  It has a fiberglass wing tube that fits into molded plastic bits in the wings and fuse.  The horizontal stab has a carbon fiber rod that runs through it, and a very cool interlocking setup that joins the stab halves and keeps them perfectly straight.  The servo pockets fit the Hobbycity HXT-900 servos I planned to use, complete with nice wire exits molded in.  There are even little molded grooves in the receiver pocket so that the whiskers of a DSM2 receiver will lay down gracefully.  All in all, PZ is continuing to evolve the foamy, and that evolution makes these stronger and easier to build with every release.

The Wildcat flies great.  It’s a little smaller than the BL mustang or the T-28, a little faster, and the wing tube pretty much eliminates wing flex even with the hopped up motor.  I used a 15% rudder to Aile mix in my X9303, 25-30% expo across the board, and I tend to fly it on high rates all the time.  The axial roll rate is snappy, it turns nicely, and gains altitude like who would not have it.  It’s also remarkably balanced, and flies inverted very nicely.

I got about 5 minutes with throttle management out of a Rhino 1350, and I highly recommend using 30C batteries if you intend to go full throttle.  I have not tried flying it with an 1850 yet, mostly because the CG is dead on with the smaller battery and I wanted to try flying it light, first.

So, when I add up what I spent, it comes to $202.30, not including any sales tax or shipping.  Shipping from Hobbycity can be significant, especially on motors and batteries, so be aware.   Also, that figure includes an inexpensive Ebay JR SPCM receiver.  If I had used an AR500, I’d be at $225 before tax.  If you were to buy the Wildcat from Horizon as a BNF, you’d get all this stuff plus a cheapie charger for $189!

So, building with Turnigy and Rhino is not necessarily the cheapest way to go, but I definitely think you are getting a better airplane at the end of the day.  If nothing else, raising the top speed from 45 to 70+ mph is worth the extra bucks, and once CustomRC produces a mount, the job of assembly will be even easier.  Building a foamy yourself over a couple of evenings is a lot of fun, as is the chance to decide what parts you would like to use.

Full build gallery here.

- Eli

My Squall, post 3 flights/1 minor incident

I have been thinking about one of these for a long time, and when Hobbypeople dropped the price a few bucks on the complete setup including vectored thrust, I jumped.

I built the kit using trusty old HXT-900 servos, and the build was mostly unremarkable.  The ARF and associated parts are all of good quality, and the manual is written in a way that I found easy to understand and use.  We used Rhino 2250 4S batteries, but you could probably use anything – the battery tray is wide, long, and accomodating.

Cutting out the decals is about as labor-intensive as building the kit, but there is good news – The provided decals look awesome, and provide needed orientation when in the air.

This is a very interesting airplane to fly.  If you just throw and go, that’s exactly what you get, and we clocked it at 82mph in straight and level flight.  It looks good, feels good, and slows down just fine for landing. 

If you decide to set your TX for high rates, and start slowing down and using them, you can do things like hover, flat spins, and all sorts of other stuff that I’m not really skilled enough to be doing at this stage of the game.  At one point, I got a little low after some of this, and had a low-speed impact with the field – this foam breaks cleanly and repairs cleanly.

As long as you keep it on low rates, this airplane is really quite easy to fly.  If you decide to start mucking around with low speed maneuvers using the vectored thrust, just remember to stay up at altitude and use power as your salvation if you get into trouble.  Flying an EDF like a 3D airplane is weird, and they do not recover from 3D space back to flying as gracefully as the prop jobs do. 

More news as my skills improve,

- Eli

This is my second E-Flite Sukhoi.  I built the first using the recommended E-flite Park 480, and I really enjoyed the kit.  It had great flight characteristics, looked great in the air and on the ground, and the thing rolls like a damned pin drill.

That said, it was a little underpowered.  The 480 got it moving OK, but it did not have the punch I was looking for, especially for some 3D maneuvers.  I ended up crashing the first model, practicing blenders way too close to the ground.  It was a bummer, but also a chance to rebuild.

I had an email conversation with Lucien over at Innov8tive Designs, and he recommended the same motor I ended up installing in my Ultimate Biplane, the SII-3014-1040kv.   With a 12x6E prop, it’s good for 70oz thrust, and about a 48mph pitch speed.

I had to modify the X mount provided with the Scorpion a little bit in order to fit the firewall – A drill press is very handly for modifying the holes.  While I was doing this work, I also brushed on some thinned epoxy to reinforce the motor mount. 

The assembly of the ARF is typical E-flite stuff, nothing noteworthy there.  I will say that the fit and finish were right on par, and the manual was well-written.  I added some fiberglass wheel pants left over from my PA Addiction, and DUB934 long 3D arms for the Hitec HS-65HB servos.

The kit gained a little bit of weight.  The Scorpion motor weighs in at 4.52oz vs. the 480 at 3.1oz.  Overall, the model weighs 30.1oz less battery, which makes for a 37-38oz AUW with Rhino and Turnigy 2200′s.  E-Flite quotes 30-32 AUW, and my old one weighed darned near 34 all up even with the 480, due to the fancy aluminum spinner I was using at the time.

I may end up adding another oz or so to the rear, depending on how the CG feels.  I added a few tenths of an ounce in bling this weekend, in the form of a character that a good friend’s daughter donated to the cause:

I’m really impressed with the way it flies, and I’m not noticing the extra weight as much as I thought I would.  I’ve flown it about 15 times since I started writing this, I never have bothered to add the addl. weight to the tail, and I love the way it flies.  It will do 3D quite easily, but it’s a lot more fun to fly it in a sport aerobatic pattern, fast.

With the additional power, and that huge rudder, it will knife edge at ridiculously low throttle settings.  With a Turnigy light electric prop, it spins up very fast, making it easy to flow between 3D and sport flying as you wish.

This model was a blast to fly with the recommended 480 motor, but with this upgrade you get so much more.  It’s a win-win!

- Eli

Turnigy powered Mustang BL

The Parkzone Mustang BL is a great looking model.  I resisted the temptation to buy one right off the bat, hoping that a small wait would result in some aftermarket parts and a proven formula to build one inexpensively.

I’m not breaking any new ground here, just condensing information I found on RCGroups and what I considered the best aftermarket mount.  There is a master thread at RCGroups that you should absolutely look through if you are considering a build.

The best value is to buy the parts as the complete airframe, the part number is PKZ1870.  I paid $79.99 for mine from Horizon, and note that when you ship there is typically an oversize charge.  The box is HUGE!  Still, you save quite a few bucks over buying the pieces individually, and you also get some labor items done for you, like cowl fitting, control horns, and decals.

The genesis of this idea was discovering the way-cool mount that Customrcparts.com makes.  I opted for the venerable Turnigy 35-36C, because I like them, and also because I had a good one on the bench

The Turnigy Plush 40 or any 40A speed controller will work fine, as long as it is slim enough to fit in the nose of the airplane.  HXT-900 servos fit right in the pockets and are dirt cheap – to date, we’ve never seen one fail in service under normal use, and they are plenty fast.

The Customrc mount is great.  It goes right in, and you can use the stock spinner and prop with the Turnigy motor.  Everything just lines up
Note – You can’t use APC props with this setup, they don’t fit, and you would need an aftermarket 2.25″ spinner.

I noticed a lot of little niceties in the parts – there are channels for servo wires in convenient places, a nice tray for your RX, and the aforementioned pocket for the ESC. 

I opted to do the optional rudder sutup, which was quick and easy.  All the parts come in the airframe kit, and I can’t think why you would not do it for the price of another HXT-900.

I used Hobbycity 3S 1850 40Cbatteries, because they fit the pocket so well.  There are a lot of well-documented mods on RCGroups that allow you to use 2100′s quite easily, I just happened to have these batteries on hand.

I used the stock 9×6 for the maiden flight, which was a joy.  It’s got great, forgiving handling, feels very nimble, and does the full suite of aerobatics with ease.  I didn’t take any measurements on the maiden flight, but for the next flight I installed a Master Airscrew 10×8, and went to town.

Awesome.  We got two confirmed radar passes at 69mph, and you can go 5 minutes at triple latte on the 1850 and still have a little puff to get home.   I didn’t get an Eagletree reading today, but we registered 41.6Ap 476Wp in static testing with the 10×8.  I bet I’ll be able to tune for a little more speed once I get some Eagletree data.

The best thing about this is the fact that you can put one in the air for about $175, but you get some substantial upgrades like more horsepower and the aluminum mount.  It’s a blast to fly, and I’m looking forward to further mods like retractable landing gear, and flaps.

My new favorite daily driver

Overall, it’s clear that Parkzone is not resting on their previous success.  The overall design and flight characteristics of this model are top notch at any price, and using the aftermarket parts, you get a chance to customize your plane with the servos and powertrain you prefer.

The Parkzone F-27 Stryker is an amazing airplane, especially at the price.

The inherent stability and good low-speed manners of this model break the traditional idea that fast pushers need to behave like lawn darts.

I build my first Stryker from parts last year, employing the E-Flite Six 2700kv motor and 3s high-capacity Rhino batteries.  With a 6×4, we were seeing 85-90mph reliably in radar passes, and the model handled great.

I started reading about the EFL Six, and learned that you can push a lot more than the recommended max of 42 amps.  I decided to order up some 4S Rhino batteries, and build a new Stryker.  I used an Align 450 K10175A heat sink, and decided to try one of the new Turnigy 85A ESC’s that have a built-in heatsink.  I also installed a motor temp probe for the Eagletree logger.

The first flight was uneventful, until I really started pushing up the speeds.  We saw a couple of 85+ mph passes, and whenever I started flying faster than that, I started noticing some serious problems steering the aircraft.   We decided that I was going to need to beef up the airframe and the elevons in specific before flying it any more.

I beefed up the structure with carbon fiber rod, and day-glo duct tape.  I applied CF tape and thinned epoxy to the underside of the elevons, which helped quite a bit.

At this point I also got a little reckless, and installed a new prop.  I had been running with a 6×4, and decided to put a 6×5.5 on there without thinking about how much of an increase that was. 

….  and it proved to be too much.

The model flew much better with the stiffer airframe, and spent the first part of the flight just getting used to it.  Finally, I decided to ‘give it the berries’, and see how we fared.

I wasn’t sure, but I thought I saw a little smoke trail on that climb.   I did a nice long power off glide, pretty much assuming that the motor was fried.  When I throttled up again, I was astonished to hear the motor spin up.  I decided that I must have been seeing things, and did another pass.

This time the smoke trail was unmistakable.   I spun it around, power off, and landed.   The motor was crispy critters, you could smell it a mile away and it was actually melting the plastic motor mount. 

In reviewing the data, it looks like I tried to push 96 amps through the motor, and the sky-writing was predictable at that current.

Eagletree graph, illustrating abuse

 I really should have been more cautious, we live and learn.

I got one of Custom RC’sStryker modular motor mounts, and this is a really nice looking part.  It is available with a 28-30mm head, a 36mm head and also a special 36mm unit designed for Mega motors.   I plan to use one of Hobbycity’s 36mm inrunners, although getting the model to CG will probably be a challenge.

More news as it becomes available,

- Eli

UPDATE 3/22/2010 -

First, a word on Custom RC.  Not only was the Stryker motor mount a joy to install and look at, these are seriously nice people to boot.    I guess they dropped the price on the Stryker motor mount by $10 recently, and decided to issue credits to customers who had recently purchased at the old, higher rate. 

Nobody does stuff like this anymore, and my hat is off to Gary and his folks. 

The Hobbycity 36mm motorwas heavy, but it balanced – Now that I have the motor in hand I realize it’s a car motor – I took it out with a Graupner 6×6 prop installed, and the thing flew great until about 100mph again, at which time it started corkscrewing all over the place.  I’ve decided that I’m going to glass up a new airframe before going any further, this airframe is trashed.

- Eli

Waiting for a Horizon Hobby order to arrive

Last week I put in a little stock order at Horizon Hobby.  I order a lot of stuff from them, and after many orders I have a real good idea of how long the shipping interval is from their California Warehouse, and also the Champaign IL location. 

For the last few years it’s been my experience that orders filled from the CA warehouse get to the Bay Area in 2-3 days, tops.  If you want something for the weekend, you order by Tuesday, and you should be set for Friday.  It is important to note that this is when you use the $4.99 shipping option.

Last week, I placed an order on 3/2.  I was really surprised when I did not receive the gear by Friday, and even more surprised when the stuff from IL showed up!

I tracked the package, and noticed that the tracking had been handed over to ‘Mail Innovations’, which is a UPS spin-off.  According to the tracking, the package has been sitting in Petaluma since 3/4.  It arrived in the North Bay 2 days after I ordered it, but’s it’s been sitting since.

I phoned Horizon customer service, and I was really surprised at what I was told, verbatim by the customer service rep:

- The tracking on Mail Innovations items is ‘goofy’, and is not really useful or accurate.  This is known and understood by Horizon.

- The rep recommended that if tracking is important to you, that you should use another method like UPS.

- These Mail Innovations packages can take up to three weeks to deliver.  I asked her to repeat this three times.
When I asked her what I should do if my order did not turn up, she said I should wait another week until Monday, 3/15.

None of this is very good for the Horizon Hobby customer in California.  

We used to be able to spend $5 on shipping and get a small order out to the Bay Area in 2-3 days.

Now, we are told we should wait 2-3 weeks for the same service, and if we don’t like that we should start spending more on shipping.

I’m sure there are extenuating circumstances that caused this, but I would expect some kind of warning from Horizon either as part of the order process, or a bulletin on their website. 

Put plainly, this change, and this poor performance is not what I would have expected from a company like Horizon, especially without notification.  And, when their customer service people tell me that the solution is just to start spending 40% more on shipping, I’m tempted to start shopping around.

**Update 5/2010**

A couple months have gone by since I wrote this, and shipping times have returned to what we always considered normal.  Couple-few days from the CA warehouse, maybe 1 or so more around Xmas.

So, in retrospect I think that the problem I experienced was a fluke.  The subsequent communication problem I had with the service rep at Horizon complicated matters, but who knows, maybe I was a little cranky that day.

Horizon has always been a solid resource for the hobby, and it’s awful nice to have reliable, inexpensive pretty-quick shipping.  Special thanks to Beth at Horizon for getting in touch and making sure that all of my questions or concerns were answered honestly by the right people!

- Eli