BH Model Pitts Special

[Doozer]

Hello All,
It's Strange doing this for an Airplane, but I'm really starting to enjoy this side of the hobby. I've been flying Planes outside of the sim for a few weeks now, and in the sim for many months. Doing loops and rolls without having to move the "collective" is such a "more bang for the buck" feeling. I've been practicing on a PZ Stinson and having a lot of fun. I had a few hiccups learning to taxi and get airborne with a tail dragger. Now I'm hoping to learn into this plane. I loved it when I saw it. I figured, I like bigger helis, so why waste money on stuff that's gonna land in the junk box?

This is my first Plank build, and it's not really a build. Scratch builders will be quick to point that out I'm sure. This is an ARF kit, but there's still some building that needs to be done. I'm already thinking I want to scratch build something, but that's another thread. So here's your warning... I know not!

A Little About the Plane and the Builder

When I first saw this plane at my LHS I knew that's what I wanted to fly. I have always had an affection for biplanes and this one really caught my attention. I had no ideal that it was a replica of a real plane. I always thought of scale as a specific measurement... i.e. if it is "x" big then it's "y" scale. I didn't think that it meant it was a scaled down version of the original. It wasn't until I had done some research on how to build the plane that I realized that a real plane called the Pitts Special actually existed and that it had quite a following in the aerobatic airplane community. It wasn't until a RC Heli Talk forum friend pointed out that my r/c version of this plane was actually a bit bigger than 1/4 scale that I realized how small this plane is actually. So I decided that I would give some background of the Pitts Special in this edit of the original post.

The Pitts Special was designed by a crop duster named Curtis Pitts. In 1943 he decided to build himself an airplane. "I only intended to build one airplane- for myself," said Pitts. Pitts tweaked the plane's design until it's first flight in 1944. Despite Pitts' intent, the Pitts special gained the interest of a few aerobatic pilots. In 1947 Pitts sold a plane to Betty Skelton to be used for aerobatics. Pitts had always painted a skunk on his planes and called them "Stinkers." When Betty Skelton bought his plane, she renamed it "Lil' Stinker," and the plane took off in popularity.

To this day, the Pitts Special has changed little in design from the original plans. There have been several iterations, and a few companies have produced Pitts Specials. However, the overwhelming number of Pitts Specials out there are "kit" built by private aerobatic airplane enthusiasts. The airplane has the reputation as being a "squirrely" plane to taxi, fly, and land. As veteran Pitts Special instructor and pilot Budd Davisson puts it,

"Once you learn to make love to that sometimes-cantankerous, little flying machine, you inevitably find that it’s more than a machine. It’s a semi-animate being that becomes a living part of your life. The boundary between man and machine, between mechanical interest and lifestyle, blurs, and you find yourself part of a community of kindred souls, all of whom have the same father—Curtis Pitts."

Hazel Sig, of the model aircraft company Sig Manufacturing said of the Pitts Special, "It's a tremendous thrill flying a Pitts -- especially the single placement ones," she said. "You kind of put them on, and you think about what you want to do and it seems like you can do it."

Curtis Pitts had the reputation of being an easy man to talk to and to become friends with. He gave away his plans to his friends stating "Friends don't sell other friends paper," even if he only knew you a few short hours. Pitt's died in 2005 at the age of 88, but his planes are still being built to this day.

Where I got my informtion:
www.airliners.net/aircraft-data/stats.main?id=46
en.wikipedia.org/wiki/Pitts_Special
www.planeandpilotmag.com/pilot-talk/grassroots/remembering-curtis-pitts.html

Black Horse Model Pitts Special - 1S 1/4 scale

What's In the Box?
It was surprisingly packed well. Even though I think the box was somewhat old and well traveled, there was no internal damage and all the parts were accounted for. This is a big plane. It's longer than any heli I have, and the wingspan, at 59+ inches is longer than any heli I have. So I'm going to have to hang it Gabe style from the ceiling. Black Horse Model has this plane listed as 1/4 scale... but I think it's more like 1/5 or 1/6 scale. Great Planes made a Pitts bipe that is 1/4 scale and their plane dwarfs this one.

Edit: The GP Pitts special is a 1/3 scale plane, and the 1/4 scale designation given to the BHPS-1S is actually small based on the 17ft 4in wing span of the full scale Pitts S-1S.

The plane is covered with Oracover. I have no clue what the difference is between Oracover and Monocote or any other covering for that matter. I was a bit surprised at all the wrinkles, but after reading a little, and some posts from you guys here, that's probably to be expected. I purchased and iron and a heat gun, and I'm going to use the heat gun as Akent suggested and take the wrinkles out slowly on low heat. It's a chilly 50 degrees this morning so I don't think I'll mind using the "heat gun" for a few hours. However, the "heat gun" looks suspiciously like a hair dryer my daughter uses, and I'm not sure I couldn't have used a travel iron on a low setting ::shrug::

One thing I will not be doing is placing all of their decals on my plane. I might airbrush some of my own artwork on it, but I'm not going to make my plane a billboard for their website. Only if they sent me the plane free and that was a condition of it being free would I put "blackhorsemodel.com.vn" on my plane. I'm not even going to put the full "Black Horse Model" underneath the bottom wing. I'm just going to use "Black" on one wing, and "Horse" on the other.

Here's a link to the Manual:
www.blackhorsemodel.com.vn/products/BH85%20manual-%28Pitts%291.pdf

Big on pictures, little on words or descriptions. It's not the worlds best manual.



Can't watch the video? Here are some pics:





Wrinkles

Here is the build price breakdown:
*1/4 scale Black horse S-1C 90-120 Pitts Special ARF Kit - $275 (Bought Locally. This includes sales tax. The kit ranges in price online and the lowest I've seen it on E-bay is $325... shop around)

*DLE 30cc gasoline engine - $300 - This kit includes an engine mount, CDI ignition, Silencer, muffler, spark plug, and a drill jig for your prop and back plate. www.troybuiltmodels.com/items/DLE30ENGINE.html

*x4 Hyperion DS20 UMD High Torque Metal Gear Servo @ $40 ea. - $120 www.rcdude.com/servlet/the-1132/Hyperion-Atlas-Digital-Servo/Detail These will bend your linkage before they bind @ 6V

*X2 Hyperion DS20x SMD Metal Gear Servos - $50 (you can catch them on sale for $40 sometimes, if you do, buy them) - $100

*x1 Futaba S9254 with voltage regulator for throttle (I had it laying around) - $100

*Spektrum AR7000 7-Channel DSM2/X Receiver - $90 -www.spektrumrc.com/products/default.aspx?prodid=spm6070

*Battery Packs (ignition/rx) - Hyperion 25C 3S 2100 - $40

*CC BEC Pro Voltage Regulator - $50 www.rcdude.com/servlet/the-1464/Castle-Creations-BEC-Pro/Detail

*JR PA900 Matchbox - Allows you to match up your servos throw and eliminates daisy chained Y's - $70 www.troybuiltmodels.com/items/JRMATCHBOX.html

*WRC Wike Ignition Battery Eliminating Filter for use with any battery type. This eliminates the need for an ignition battery, allows you to set up a radio kill switch, and allows you to use any battery type (li-poly; li-Ion; NiCad; A123; NiMh). $50 - www.troybuiltmodels.com/items/WRCIBEFV2.1.html

* X8 6" servo extensions - $4 per pair - $16 www.troybuiltmodels.com/items/TBMW.5.html

* Tygon Fuel Tubing 3ft - $7 (price is for 6 ft, but you can always use spare tubing. Eventually it will go bad) www.troybuiltmodels.com/items/TUBGASR.html

* Sullivan Heavy Duty Aluminium Fuel Tank Stopper - $15 www.troybuiltmodels.com/items/SULFUELSTOPPER.html

* Dave Brown 4" Vortech Aluminum Spinner $46 (LHS) but you can order here:
www.horizonhobby.com/products/2-blade-alum-spinner-4--DAV8240

*APC 18X10 Prop - $23 (LHS) but you can get here:
www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXCGK4



Tools and Supplies I used on this project:
-Coleman Fuel
-Royal Purple 2 Cycle Synthetic motor oil
-Phillips Driver Small/Med
-NN Pliers
-Slotted Driver (for adjusting needles on carb)
-Epoxy (5 min for the quick Jobs 30 min for the jobs you can afford to wait).
- CA (Thin for the hinges (if you use the CA Hinges provided) and I use thick on everything else)
- Gorilla Glue (If you've got the time to wait, this is good stuff)
- Shoe Goo
- Soldering Iron and solder
- Covering Iron or Heat Gun
- Dremel and Dremel Press (I use the press for installing Robart hinges)
- Velcro
- Gel Servo Mounting Tape
- Zip ties
- Battery Charger and Balancer
- Flash Light (I use one that attaches to my head)
- Packing tape
- Airplane Work Stand
- JR X9303 Transmitter
- Paper Towels
- Tounge Depressors and Popsicle Sticks
- Mixing cups
(You could spend several hundred on that list, very easy, if you don't already have those items).

Total:
Give or take a few dollars: $1330
I tried to work shipping in. But your milage may vary. Troy Built Models has very expensive shipping so if you buy from them try to buy in bulk. Also, that's the price for what I have in the airplane only. It doesn't include the tools, supplies, Fuel/oil and radio. I can't see someone taking on this project without most of those tools and supplies.

[Doozer]

The Build

Wrinkles

Since this is an ARF is came mostly built and with the covering already shrunk to the frame. Black Horse is a Vietnamese company so there's no telling how long it's been in the box waiting to be sold to the end user (me). The covering in this case is called Oracover, and while waiting to be purchased, the planes covering developed wrinkles.

So before I started putting the plane together, I thought it would be a good idea to get as many wrinkles out while it was still in pieces. Here's how I did it:



Pics if you can't watch the video:







I started off using a heat gun, and that didn't work well for me. I was a little scared of burning a hole in the covering or warping things, so I ended up using an iron.

A Bit About the Manual

There are tons of pictures in the manual, but they use words sparingly. It takes some getting used to, but it sort of works. The one good thing about there being very few words is I'm not trying to decipher "Chenglish."

If you've never put together and ARF airplane before (which I haven't), then you may fumble around a bit before things become clear. I read, and reread the manual several times before I got started. This helped me to understand and expect what was going to happen next. However, they do take some leaps of faith with your building ability. I imagine this is why they put the caveat in description of the plane... "This is not for a beginner" (which I am).

I originally decided I wasn't going to follow the manual in order for workspace reasons, but changed my mind. Not because you shouldn't, just because I didn't want to get lost and forget something. An experienced builder could probably put this thing together without the instructions. I just decided that going in order would be better for me, and for those that might follow this thread with a BH pitts of their own.

However.... I did decide to skip a step. I wont be using the CA hinges that came with the kit. Now I know that they work, and many many people have used them without failure, but I've bent plastic back and forth too many times as a kid to think there isn't going to be a breaking point sometime down the road. It's a personal preference (underline, bold, quotes, italics). I just don't trust them and they would detract from my experience. I'm not going to argue their validity with anyone... it's a personal choice. I will be using Robart hinges. www.robart.com/products/316-hinge-big-bag-combo

The Wings

I suppose you could start with any wing panel since there are four of them. I chose the bottom right (bottom left if you have the plane belly up). I quickly realized that if I was going to use the Black Horse bottom wing decal, I'd have to put it on now. If I put it on after I got the servos installed it would be a real pain in the ass. The manual sort of covers this in image, but never says anything about apply the decal straight away.


Make sure that you have your servo mount in the wing without the screw holes pre-drilled.


There is an orientation as to which way the mount goes in. You want the servo horn slot closest to the wing tip.


This is the way the wing should look before you apply the decal


Because I'm only using Black on one wing and Horse on the other, I had to center the decal on the wing. I placed the bottom edge of the decal along the edge of the aileron box. This worked out quite well.


Using a brand new Xacto blade, I cut out the servo mount from the decal.


Once you have the servo mount removed, you can cut the slot for the servo horn. You'll have to cut through decal and Oracover. Luckily, none of the letters were positions over the slot.


Then I installed the servo onto the mount. There is an orientation. The servo horn should be closest to the leading edge of the wing.


You will need servo line extensions. You can solder them or connect them. I chose to connect them for now, but see the value in soldering them. It would suck if for some reason they pulled apart.


Because I was connecting them, I attached a weight to the end of the servo line extension (a fuel filter).


I dropped it through this hole


a little hard to see but it comes out here.


Clearer here


Pre-drill the holes for the screws. Make sure you measure your screws. Unlike some other manuals I've used, this manual does not use "actual size" pictures when showing you which screws to use. You could easily use the wrong screw here and pre-drill a hole that is too big.


You'll need to pre-drill in two places. Once on the mount itself (X4 screws) and on the mounting box inside the wing. You may need to pull the covering away, but there are marks to show you where to pre-drill.

Now just repeat these steps for the other three wing panels.


Nov. 8 2011 Changes.... sorry went to a LHS and picked up Robart Hinges so I'm in the process of installing them. I have one wing panel complete. Also, I changed to servos I'll be using. I forgot that I had two Hyperion DS20 UMD's (high torque), and two Hyperion DS20x SMD's laying around. I'm going buy two more UMD's to put in the wings and use the SMD's for the tail (Rudder and Horz. Stab). Both the UMD and the SMD have more torque at 4.8 v than the recommended Hitec has @ 6V. Here's the comparison:
www.servodatabase.com/compare?servos=896,1015,1016

Here's a quick video of the completed wing:


Nov. 15 Progress:


Nov. 19 progress:


Control Surface Hardware

Here are some still images of the control surface hardware installation:
planetdoozer.com/Pitts%20Build/controlhardware1.jpg [/img]
The hardware is the same on all control surfaces.


The holes for the control hardware are pre-drilled


These grommets go on either side of the holes


Pop the bolt through, then slip the other grommet and a nut on to the bolt. You don't need to worry about forcing the the grommet in. As you tighten the nut and bolt the grommets will seat properly.


Now pop the other nut and control horn on. The control horn is threaded so it's easy to get a 90 degree angle with the control rod.


add the clevis to the rod and you're done

The JR Matchbox


There are a couple of ways to set up your aileron servos. You can daisy chain 4 "Y" harness and then program your servos if they are programmable. If they aren't programmable you will have to work hard at getting your throws to be close to the same. You'll need some luck and patience to get them exact.



With the matchbox, I can match up to four servos from the aileron servo port. The servos don't even need to be the same type (though I'm not sure I'd recommend that). Each servo port on the Matchbox is assigned two numbers. The first number sets your neutral position and your end points. The second number is for servo reversing.



By rotating the dial (pictured above) to the servo I want to change I can increase or decrease the throw by moving the aileron control stick all the way left, or all the way right, then pushing the increase or decrease buttons. If I leave the stick in the neutral position, I can set the servos position when neutral. This is helpful if you can't get your control surface exactly neutral mechanically.

Once I have my control surfaces set up the way I like want them, I rotate the dial clockwise passing 9 until I arrive at zero. Then I power off.

Main Landing Gear


The main landing gear is made of iron and easily the heaviest single piece in the kit. It's mounted on the bottom side of the fuselage in these to routed grooves. It's a tight fit and you'll have to cut slits in the Oracover.


Unfortunately, holes are not pre-drilled for the plastic mounting straps.


I only put one screw in each strap, then mounted the gear. I added the additional screws in a criss-cross pattern so one end wouldn't pop up.


There is a groove that the straps fit in, but the groove is fairly big so you have a little wiggle room. This is what they look like tightened down.

[The Dude]

Planker!
Looking forward to the pics, maybe it will inspire me to try my mini telemaster, that is all from me in this thread, I will watch.

[Doozer]

Haha, copy that!

Just a real stress relief from helis. I still refuse to join that plank club by my house. Anyway, got a few pics uploaded just gotta edit the first post.

[19000rpm]

Congrats on the new plane and being the first in the plank builds/mods section.

Now we have a place to post plank mods. Thanks Dave.

Speaking of Stinsons; I thought you might enjoy this:
I was going to test fly a PKZ Stinson for a friend of mine to check his trims. We were flying off grass. Even knowing that it has an inordinate amount of prop torque, having seen your vids, it still surprised me. I had what I thought was plenty of counter rudder and it still turned left like it was on rails. One of the wheel pants hooked on some grass and it cartwheeled. Broke a wing tip and a chunk of horizontal stab too. I have a lot of experience flying tail draggers and this is the first time anything like this has happened with a stock plane. Live and learn.

On with your build!

[akent]

Hey Doozer, if you are going to fly 'crunchies' (what I call wood/fiberglass) planes, then you need a heat gun and an iron to get those wrinkles out.
A heat gun works best for wrinkles on larger areas, and believe me, they all will have wrinkles. If not out of the box, then the first time in the sun. I use an iron for getting wrinkles out of tighter places, like wing tips and the like.
Go easy on the heat and it's a good idea to use a soft wool mitten with the heat gun to get the covering to stick to the wood. You don't need this with the iron.
You just heat it up until the wrinkle just goes away. Then quickly rub it with the wool pad while it's still hot. You could use a soft sock, too.

I have one of these mittens:
www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXHZ21&P=SM
I use this heat gun:
www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXHZ16&P=M
And this iron:
www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXHZ17&P=M
With these iron covers:
www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXHZ20&P=M

I've had a couple of planes look like those Chinese wrinkle dogs out of the box before! They were all perfect after some heat.

Often, if you crash a crunchie, they can be fixable. You now have the tools to recover the plane!
Kent

[Doozer]

Great minds think alike. I hadn't read your post but stopped at the LHS on my way home from work and bought the gun, iron, and iron covers. I figured I could be uncool and use an oven mitt. I watched a few how to videos at work. The general consensus of most in other forums was that the iron was better to take out the wrinkles. The guy at my LHS, who is building the same plane said that the gun on low heat with the deflector on was fine. He said that's how he did it, but.... i'm a noob so...

[Doozer]

Added the unpack video and edited the original post to look more like a build thread. I'm going to spend today taking out wrinkles and watching T.V.

[akent]

Doozer, Oracover is the same as Ultracote, in my opinion the best covering material.
Monocote takes a lot more heat to shrink, and can become loose again over time.
Ultracote doesn't do that nearly as bad, and uses less heat to shrink.

Oh, and your new 'hair dryer' can literally catch your hair on fire, or at least frizzle it into piles of ash!!!!!

Good stuff!
Kent

[Doozer]

Nov 6, 2011 11:15:40 GMT -6 akent said:

...

Oh, and your new 'hair dryer' can literally catch your hair on fire, or at least frizzle it into piles of ash!!!!!

Just saying!

I switched to the iron. It's working better for me, I had less control of where the heat was going, plus it was friggin' hot. I'll need a little more experience before I try the heat gun again.

[Solitaire]

Black Horse Model has this plane listed as 1/4 scale... but I think it's more like 1/5 or 1/6 scale. Great Planes made a Pitts bipe that is 1/4 scale and their plane dwarfs this one.

From what I understand, the real Pitts has a 20 ft wingspan, so yours would be 1/4 scale at 59". The GP Pitts has a 68.5" wingspan and they call it a third scale (from the GP website), although I think they need a couple+ more inches of wingspan to make it a true 33%'er.

[Doozer]

I did a little research last night and this morning. I wanted to find out more about the full scale plane. There are several versions of the Pitts and the dates range from 1947 to present. The S-1S has a wingspan of 17ft 4inches, and weighs 1150 lbs www.airliners.net/aircraft-data/stats.main?id=46. Its small plane so the 1/4 scale designation based on wing span is actually small, but deceiving to someone that may not know how small the full scale plane is. The 1/3 scale for the GP Pitts is just about spot on. Actual plane size is not something I thought about when I purchased the plane. I new nothing of Curtiss Pitts or that this was a real plane. This adds a new, and interesting side to the hobby.

I was interested to see if the wing area was 1/4 scale since the weight is not. The wing area of a full scale Pitts S-1S is 98.5 sq. ft. The wing area of the BH Pitts special just a scosche under 9 sq ft.

I will be editing not correcting the original post since this is a learning experience for me and perhaps someone else as well. Thanks for the corrections Sol.

[Doozer]

Added servo and decal installations to the build section. I'm also going to add some history about the plane in the original post, but a little further research is required.

I'm putting the build on hold for now. I'm waiting on Robart Hinges and two servos. It will be a week or so.

[Doozer]

Nov 8, 2011 10:41:42 GMT -6 Doozer said:

.... I'm also going to add some history about the plane in the original post, but a little further research is required.

Added

[Doozer]

Found Robart hinges locally (another LHS not my usual). Installing them now. I'm not sure that I'll take pics and add how I installed them. It's my first time and I don't want to lead anyone down a bad road. I will post links to installation videos. I used Epoxy... thinkin maybe I should have used Gorilla Glue (original). We'll see how it holds.