congratulations DNTS
 

I worked all day on mine and then I saw your post and was thinking, gee, I hope my maiden flight goes as well. Nothing like going to the field and doing a maiden flight and then getting to think about the next time. I am installing to Fuji BT 50 S-A, just like in the Feb. MAN article. I had ordered Futaba S9303 servos for the ailerons and S9001 for the elevator and rudder, but then a post on this thread suggested that I go with metal gears on all servos. So, I tried to order S9303 all the way only to find that these have been discontinued. The only replacement with the same torque and metal gears were the S9405's. These are a good bit faster so I I decided to put the 9405's in the ailerons and rudder. I put the two 9303's I had already purchased in the elevators. So far everything is going together just fine. I also pinned the firewall with 10 1/8th" dowel pin as recommended for gas engines. As I am putting this ARF kit together I have to say that I am very pleased with how thorough the directions are and how well everything fits so nicely together. This has been the best ARF kit I have ever put together, so far. :) It looks so darn good too.

Again, congratulations on your maiden flight and glad you are pleased with the engine performance. I had thought about using an OS 160; great engine. After reading the threads on this post and the article in MAN I decided to try a gasser as a first time project.

[email protected]
Roger F. Woodward
RCRC Huntsville Al.

GP pitts
 

o well

GP pitts
 

I thought of using a gasser as well but decided not to for two reasons. First, we had some bad experience with a gasser recently, and although I think I can manage to make the receiver noise proof, the whole airframe is complicated as is and I do not want to risk it in favor of cheap fuel. Second, I store the plane at home (in my 9 months son's room) and the smell of a gasser is something neither me nor my wife will tolerate. The MVVS 1.60 can ingest a diet of 10% oil FAI fuel (no nitro) so mixing my own fuel (as I do for my other 2 and 4 strokers) will bring the runnig cost to the gassers ballpark.
I now need to get a pitts style muffler for the engine. I saw Bisson makes such a mufffler to fit my engine and I might order one soon.
Happy flying to all.

GP pitts
 

Hey DNTS, I have to ask. What happened with the gasser at your club?

Also, my choice in the gas engine was not so much because of the fuel economy. I had never tried one and felt this would be a good model to try it on given all the comments, good and bad, about using a gas engine on the Pitts. The Fuji really does fit well in the cowling. I will keep this model out of the house so no problem with the gas smell. I have heard negative comments about the smell being a problem if you have to keep a gas model stored in the house.

GP pitts
 

Hi rfw1953
What happened goes like that: My friend, and the owner of a MVVS 2.15 petrol mounted it on a brand new giant plane he made (he produces fiberglass models). This giant's wings span almost 10' and its a really impressive model. This was supposed to be the maiden flight of the new model and the engine. The radio we used was Futaba PCM (bad choice for gasser). The installation of the engine, ignition and received was ok (over 8 distance). I tested for range with engine both idle and full RPM and it looked ok. I wanted to program the failsafe but my friend who is a stubborn mule dismissed me as being paranoidic. I decided I would still do that once the ground break-in finishes. I went to get something from my car when I noticed him taxiing the plane to the runway. I asked if he was going to take off and he said he only wants to taxii the plane to figure out the handling etc. I guess he then had a short circuit in his brain because instead of taxiing he decided to take off. The plane gained speed and he lifted off. Once about 20' off ground the radio locked and he went full throttle into ground. A post mortum revealed that neither the plug nor the ignition assembly had a series resistor, which can account to the radio lockout. The wing survived and is in service now on a second plane he made (he didn't break the mold after he made the first one...). The engine was converted to glow and is working flawlessly and very powerful (over 4HP with 20x8 prop).

GP pitts
 

Believe them or not?? (post # 4)

I have built and flown the GP 1/3-scale pitts Special ARF for a MAN Field and Bench review and have it outfitted with the Fuji 50cc gas engine. I like this combination. I believe the weight of the Fuji is around 5 pounds and my finished flying weight was 17 pounds 2 ounces. This is a 30.2 oz./sq. ft. loading. The model flies wonderfully on a 20x8 Menz or Moki Prop. I flew is several times but aft 6 flights, the firewall came loose. I reenforced it with epoxy and 1/8 inch plywood and screws. Since the fix no problems. I also cut open the top wing to check the cabane screw location as per the GP weblink warning and reenforced that area also! Personally, I think the G-62 would be too heavy for the model. A G-45 would do the trick! Look for the review in the February issue of MAN. Gerry Yarrish



*****Above is a quote from the author of the MAN review******

Funny, none of this was in the article.

Fuji 50, prop hub length/cowling line up?
 

Schmacka,

I too am assembling this model with a Fuji 50. What size prop hub extender did you use? The MAN magazine article writer said he used the optional long shaft , 2 13/16". So, I ordered the same. It is way too long and sticks out well past the cowling. I then tried the shorter stock hub extender and it too was too long 2 7/16". The optional short extender is only .039 inches shorter than the stock extender. The Fuji 64 comes stock with a 1 9/16" extender that also fits the Fuji 50. I think this works out to 0.51" shorter than the stock extender.

I have one of the new models with the improved beefed up firewall. From looking at it, compared to the pictures in the MAN article, it appears the firewall mounting box is longer on the new models. I have nothing to go on other then comparing what I have to the pictures in the Magazine. I posted a thread on this subject and one person responded suggesting the mounting box is the same on both the original and newer models. Something sure isn't right or the long shaft would have fit as the MAN writer said. My mounting box extends 2 3/8" from the fuselage firewall.

I think the Fuji 64 stock extender will do the trick, but haven't gotten to the point of mounting it yet to check it out. Thought I would ask to see what you used and how well everything lined up.

One last thing. Some have suggested that you should fiberglass the firewall. I have never done this, but I did install 10 1/8" dowel pins and added tri-stock and additional epoxy on the inside of the mounting box. My thinking on this is that with the new reinforced firewall, dowel pins and epoxy, this should be OK. What do you think?

GP pitts
 

G-62 weights 5 pounds & if im not mistaken the g-45 is about the same, I fly mine with the g-62 & its just fine. More power than the fugi 50, some member of our club are flying the fugi 50 on the pitts & the g-62 has quit a bit more power. The g-45 is only 4 oz lighter than the g-62.

Gil

GP pitts
 

What is the total weight of your Pitts and how does it fly? Mine is 18.1 lbs dry with a Fuji 50, 7 HS-77BB servos, B&B muffler, and a smoke system. I have not flown it yet and am a little concerned with the weight b/c GP says that "it is not a pilot friendly plane over 18 lbs."

Also, right now it is a little nose heavy at its recommended forward limit. Is this something I need to be concerned with on this plane? I know on some of my other planes it actually helps.

Heres a nice pic of it!

GP pitts
 

Thaflyer:
I have my cg set @ 5 1/2 inches, my plane weights 18# dry & 21# wet with 24oz fuel & 24oz smoke oil. I have a g-62, 8-hobbico 110oz/in servo's & 1 standard, tme smoke with 24oz tank right on cg, dual reciever batteries & switches under cockpit floor, I found the plane to fly good, but I only fill the smoke tank about half full to keep a little weight off of it & try to burn all the smoke oil before landing. I have had to land right after take off to make engine adjustments with both tanks full & it was quite a hand full on landing.
Hope this helps
Gil

Thaflyer:
Make sure to install some flying wires on the tail feathers, some flyers have lost complete stab/elev. halves in flight, the supplied wires aren't any good, I used 35# leader wire for fishing leaders from wal-mart, works good.

GP pitts
 

Hi Andrew,
Flew my Fuji 50 powered pitts yesterday. I hung it on its prop twice, did a couple of very sloppy waterfalls and great inverted flat spins. I forgot what mine weighs but I posted it on that thread you helped me post my pictures to. I'm only using 5 HS 605 servos on a 6 volt battery. I wonder if I could a crisper start to a Lomchevoch with better servos.
rfw1953 I mounted my fuji on the greatplanes rubber shock absorbing mount without a box and with the standard extension. It came out fine and the cowl fit ok. Mine is nose heavy and I put an 8 oz chunk of lead in the tail but took it out fear it would fall out. I've read on a previous thread of a guy who mounted his fuji right to the firewall and found the balance just right.
Seems every time I fly something else breaks. I just replaced all the tail flying wires with 1/8 and 5/32 copper tubing. I also replaced the main cabane struts with 1/2 copper tubing. Finally it all seems to be holding up.

GP pitts
 

Andrew,
I tried out 4 props last week and found the Master Airscrew Simitar 19X8 to have far more power than the 18X6-10, 20X8, 22X8. I've never seen a Menz or other exotics but a $20 I thought the 19X8 was good.
Your plane looks sharp.

RC/Dragonfly
 

Thanks for the info on the prop hub. I can't imagine why mine has such a problem fitting everything in the cowling. I checked it out tonight and may have to have a machinist shave 1/4" out of the short prop hub that comes with the 64. W'ell see.

Was very concerned about hearing how you are having breaking problems. Not good, but info like this will cause me to really keep a close eye on things once I get her finished. I decided to fiberglass the firewall after getting some good info on how to do it. I added tri-stock on the outside of the firewall mounting box where it attaches to the the fuselage. I will then add the fiberglass tomorrow night. So far so good. Also added the dowel pins G.P and everyone else on the thread has encouraged.

As for the wires, well, I was thinking about not using them. The directions say they are for looks and not for strength. Sounds like you are using them to add strength. Yes? No?

Do you have one of the newer models with the new ca bane struts and still had to use copper tubing even after the new hardware and after they beefed up the mounting area with hardwood???? Gee, I hope this isn't the case. Please tell me more. A friend of mine who has much more experience than me discouraged using the rubber engine mounts because he suggested they would cause more vibration by allowing the engine to move around on the mount. One would think not, but maybe this actually exaggerates the vibration because of the loose fit. He encouraged mounting directly to the firewall with nothing between the mount and the firewall other than the metal engine mount. Just a thought and not proven yet as I am still assembling, but not using the rubber mounts.

Thanks for the help.

GP pitts
 

Fascinating! I suspected that the rubber mount may be actually worsening things. I wonder! Can anyone else with experience with this mount answer this question? It sure woulld be nice to lose the mount and get the CG back another 1/2 to 3/4".
Did you check out the picture of my engine mounted to my pitts?
My Pitts is the old Pilot kit and the cabane struts are slightly different from the GP kit. You can see a picture of my plane on the same thread. My cabanes struts are held on by 6 not 4 screws.
I think the tail struts are functional but I'm just quessing. I made a mistake on that last message and my copper tubing is 3/8 not 1/2".

GP pitts
 

Roger,
I omitted the mounting box on mine and am unsure if the dowels you are referring to are on the box or the firewall. By the way I ordered the fiberglass cowl from GP and it fits perfectly on my plane except for the color scheme so I'm fairly certain the GP Pitts are built from the old Pilot kit specs.

GP pitts
 

RC/Dragonfly,

I used the Fuji 64 prop hub extender and after cutting out the cowling tonight it lines up perfectly. Whew! Glad that ones behind me. I called G.P. today and they didn't have any info on the mounting box length. Then called Gary Yarrish, the writer who did the MAN review. I hope I spelled his name right. Anyway, he was very nice and said he had no problem using the stock extender with the Fuji 50. He did mention he thought his plane was one of the original models so I still think the mounting box on the new planes has been extended to make room for beefing up the firewall on the mounting box. I had one guy say they are the same, but then why would I have this problem with the cowling? It can only be that the mounting box is farther away ( longer) from the fuselage firewall. :rolleyes:

I understand you removed the mounting box and that may be why you didn't have any problems with the extender. I decided to keep mine on and reinforced the firewall at the end of the box with the dowel pins. Still planning on fiberglassing everything to for reinforcement.

Good luck getting some help on the rubber mounts. I will be watching to see what those with experience have to say about it.

Balancing the Pitts
 

Schmacka,
When the Pitts is properly balanced, what is the incident angle of the horizontal stabilizer? Hobbico tech support is not open today.
Regards,
DGO

0 degrees
 

For what it is worth I balanced mine so it was 0 degrees at the middle of the balance range.
Empty.
Flies good.
This had me put my battery packs in front of the pilot flooring.

GP pitts
 

Haven't read to the end yet, but thanks Dick for you reply. I knew what you meant by " bite your tong" but it was good to hear it from you. You can only review the plane that YOU receive. Perhaps the manufacturers send you "blueprinted kits", i don't know. DO you think they hand pick the ones reviewers get? Anyway, biplanes are aerodynamic bricks by nature and most glide like a well trimmed coke machine. So, yea, your going to bring then in a little hotter than your mono plane. My guess is, the pilot who was told to think twice about it was having his skills reviewed not the GP PITTS. Love those bipes. I have the cermark pitts with a saito 180 ( lots of mods, but easier to hall around). L'll get down now but thanks again Dick and keep reviewing, lots of us will keep reading.

GP pitts
 

i have read all the posts to this thread. it is amazing how someone who starts out reading this thing starts second guessing himself on buying one of these planes. but after reading for about an hour i think im going to buy one.

What i dont understand is if most people are worried about weight then why dont they go with a non Gasser. i plan on putting in a MOKI 2.10 pussing around 5hp but keeping the weight down.

does anyone know how the mods are now that GP has done some changes to the ARF?

and has anyone ran a motor equal to the MOKI 2.10 on this plane and how did it do?

thank you (everyone) for the great info!!!

GP pitts
 

All gassers are not heavy,,I am using a ZDZ40 and have all engine components(batt,ignition,switch,fuel dot) mounted on the box,and I had to remove the two elevator servos and and install one hitek MG under the pilot seat with carbon fiber rods to get it to balance without weight added to the nose as mine was gonna take 9.5oz added to the FW to balance it,,I chose to move things instead of adding weight,,I have a 1600MAH batt and receiver as close to the engine ignition as I dare as well(10-12inches), all of this tells me the ZDZ is light

GP pitts
 

I have a US41 on mine and did not have to do anything differently to balance it. I have 4 four servers in the tail, the receiver and the battery pack are mounted under the cockpit as per directions. I have no concern about weight, mine came in right at 15lbs and flys fantastic.

GP Pitts
 

Anyone Check there wing incidence,With my Stab at 0 degrees the top wing is 0 degrees,but my bottom wing is at 1.25 negative degrees.Is this anything to worry about?

Terry

Pitts Wing Incidence angle
 

It appears I have the same condition with my Pitts. After addressing all the other concerns, My flight today was not good. Level flight at half throttle required 1/2" of down elevator trim! Inverted required even more. Roughly checking the angles indicates the bottom wing is negative in relation to the others. I'll have to get a meter to check the angle accurately.
Generally, when a bipe lower wing and stab are at zero to the thrust line, the upper wing is up to three degrees negative. I'll post results when completed.
Running Moki 2.10 with 5% Omega, K&B 1L plug, Bisson Muff, Hitec 475 servos in the wings and rudder, 545's with one reversed for the elevator. Some personal but no special mods. Dumped the OEM spinner in favor of a white 4" Top Flite Warhawk spinner to eliminate the horrific vibration. Easy lift-off and easy landing. More in-flight checks to come
Regards,
DrGO

GP pitts
 

Malin , I read your post and it sounded so familiar. I too started out wanting this ARF and then heard so many things about it I decided against it. Then I read most of the post on RCU and decided to go with it. Never had a complaint. Only problem was that I crashed due to my own stupidity. Long story not worth going into. Anyways, I bought another one and will assemble after I finish the project I am am on. I do plan on using Robart pin hinges in the next one. I didn't have any problems with the standard stock hinges, but have read enough to believe a change is warranted. Also, the new version stock mods worked well. Only real change I made was to beef up the firewall. I modified the stock spinner so that it works more like a Dave Brown or True Turn adaptor with a threaded hole in the the prop bolt and then a long sockect head screw to secure it. Can't help you on the Moki. Good luck and good of Bipes.