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

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.

I’ve flown mine about ten times now, and I would say that landing smoothly is the biggest challenge.  One tip I can immediately recommend is to pull BACK as soon as the main gear contacts and the wing has stopped flying.  If you don’t pull back, the tail likes to float and the model tips forward onto it’s nose.

I wanted to fly the BF-109 a few times before trying the flap option, and after dumping the 109 on it’s nose a few times this weekend (plus 2 good landings!) I was ready to give it a shot.

The gray tape that covers the aileron servo wires does not survive being peeled back gracefully.  Plan to get some new tape in a similar color before you start.  You will also need a servo Y adapter, a pair of sub micro servos (I used HXT-900) and the pushrods and stuff that came with your kit.  The manual says you need to buy the linkages for flaps, but everything I needed came in the box of my BNF example.

The first brain teaser is how to make the flaps work, considering that the Ar500 is only a 5ch reciever.

On a DX6i, the answer is to plug the Y harness into the ‘gear’ channel on the reciever.   Then go into the flap setup in the DX6i, and set the flaps to 100% down.  Most airplanes need some down elevator to prevent the model from ballooning up when you apply the flaps, but this particular model does not with 1/2″ of flap travel.  I set the correction value to 0, and it stays level, hands-off.

Next, you need to mix the flap channel with the gear channel.  I put this on Mix1, set it to active and 125% down.  Lastly, I reversed the gear channel from the ‘SETUP LIST’, ‘Reverse’ menu.

The mechanical part is pretty easy, too – Place your servos, route your Y harness, and mount the control horns as per page 14 of the manual.  I left my RX powered up so I knew the ailerons were centered as I set it up, and cut the flaps out as per the recommendations in the manual.

With the clevis connected to the third hole on the flaps, and the flap->gear mix set to 125%, I’m getting about 13mm of travel from the flaps when deployed, which is close to the PZ recommendation for half flaps.

My DX6i only has a 2-pos flap switch, and I decided to leave this at the more conservative setting until I have had a chance to fly the model.

Wrapping up the modification, I moved the clevis from the outer hole to the second from the bottom on the ailerons, and overdrove the aileron servos a little bit to get the PZ recommended 3/4″ (19mm) travel out of the ailerons.

This morning, the Winter storm that has been hitting Northern CA took a break, so I rushed out to the field.   I didn’t use the flaps for takeoff, but I flew around with them and did a bunch of approaches.  The flaps do slow the model considerably, and it takes out some of that low-speed wing tipping that everybody is noticing.  Again, there is no elevator correction required at 1/2″  flap travel, I wonder if it will be required when I dial the flaps up to 3/4″. 

It will be a few days before I figure it out, because in the gray skies I got disoriented and had a little mishap.  Thank God Horizon has spare parts in stock…

Please don’t take my numbers as Gospel, and I hope this article helps some folks wrap their head around the custom mix they need to do in the DX6i.

- Eli

**Update 10/26/09 – Crash repairs consisted of a new fuselage and wing

In this iteration, I put the clevis on the inner hole on the flaps and ailerons, and over-drove everything to 125%.  This yields 1″ of flap travel, and just over 1″ of aileron travel.  The aileron roll rate is quite manageable, and there is still no need to dial in an elevator correction with the flaps. 

My 109 on approach with flaps deployed

The flaps slow the model down, but the tip stalling is still there and you still need to land under power.  An experienced pilot friend of mine suggested that I cock each aileron up a few degrees to see if that tames the stalling a little, and I’ll be trying that this week.

Keep the shiny side up,

- Eli

Zeke was the one that came up with this, I believe that some of the info came from wattflyer.com. 

Shopping list.  All the power train stuff comes from Hobbycity.

Motor: http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=3886

It can never hurt to have a spare shaft: http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=6488

ESC: http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=2165

Battery – Any good 3s 2100 or 2200MAh capable of 20C will do – these are inexpensive and good: http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=6306

Servos: http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=662

Prop (contraversial): http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=8097

Four channel reciever of your choice.  I used a JR RS6UL.

Stick of 10mm balsa, and longer motor mount bolts.  I did not measure them (!) but as I recall they were about 2.75″ and there is plenty of room for length back there.  Sorry for not documenting this better.

Depending on if you are upgrading an existing T28 or building one from scratch, you may or may not need airplane parts.   I got mine here.

http://www.redrockethobbies.com/Parkzone_T_28_Trojan_Parts_Listing_s/496.htm

You may want to get 24″ of 3mm CF rod to reinforce the wing.  I did this, Zeke did not and they both fly fine.

Lastly, do not forget to download a copy of the manual, if you do not have it:

http://www.mirafiori.com/~isaac/rc/PKZT28TrojanManualHiResFinal.pdf

On to the build!  In all truth, mounting the motor and modding the cowl is the only real work to this.   Cut the 10mm balsa into four pieces, and drill a small hole in the center of them.  These are going to space out the new motor, but still allow you to use the stock motor mount.  I like this system vs. fabbing up a new mount, because the factory thrust angle is maintained, and you also get the benefit of parkzone’s engineered parts.  In an accident, the motor mount is designed to shear, and hopefuly prevent the motor or the firewall from taking the hit.   You may also consider just cutting the balsa into 2 pieces, and letting them span the mount as you can sort of see in this pic: http://isaac509.smugmug.com/gallery/7306689_7XNyX#469920027_tyLZf

The motor is only going to line up with the factory mount on 2 holes.  We were a little nervous about this, but decided to install it nice and tight, with blue thread locker.  This has not been a problem, but it’s a good idea to check them before each flying session. The more enterprising may want to solve this problem.

 Next, it’s time to employ your Dremel, and relieve the cowl so that the bell of the motor will fit. 

The rest of this stuff is pretty routine.  If you want a more rigid wing, I recommend pulling out the fiberglass spar and reinforcing with CF.  This can be accomplished with flat or round stock, your choice.

Also, it’s important to look at the area where the wing bolts to the fuselage.  My fuse started to get a little loose after 5-6 flights, and I see stock T28′s with some miles on them that seem to need some help there.  I like to use cloth first aid tape and a little bit of 15 minute epoxy like a poor man’s fiberglassing treatment, it seemed to work great.  Lastly, it’s sometimes nice to line the wing saddle with foam tape just to keep the wing cushioned and stable.

The rest of the assembly is routine.  Put a piece of first aid tape over the battery holder area, as the fuse likes to split there.  The ESC will fit right into the stock pocket, and gets a little bit of cooling air there.

We ran this up with the three bladed prop and saw 452watts WOT.   Flight times on a 2200 are about 5-6 minutes with the thing rammed to the firewall the whole time.

Let’s talk about the prop contraversy for a sec.  Just about everyone will tell you that you wil get better efficiency and more speed if you take the three blader off and go with a different prop.  I understand this… and I don’t care.  This airplane looks cool with this prop on, the combination is very rewarding in flight and the sound of the three bladed prop seals the deal for me.  I would love to hear comments and or success stories regarding this. 

So, in summery, you can build a complete ship at a very inexpensive price that will quickly be one of your favorites.  The Parkzone T-28 is a winner due to sweet, forgiving flying characteristics, scale looks, speed and durability.

This modification does not compromise any of the good qualities, but it does make the thing a lot faster.  Some of the guys down at the field have Power 10 motors on the T-28′s and we are flying rings around them. 

Complete gallery here:

http://isaac509.smugmug.com/gallery/7306689_7XNyX#469910197_US9Sq

Enjoy!

- Eli