jpjamie

TOTALLY agree Sailfish! There have been a couple of workarounds for this (now) well documented tailwheel issue. One is to drive it with a dedicated servo located in the forward fuse close to the rudder and elevator servos and run a pushrod aft to the tail wheel control horn. Glue a cross brace to the tail wheel bulkhead with an inserted bearing above the stock bearing and hook up the arm to the servo. I tried to keep the weight lower by using a piece of carbon fiber tubing which just happened to slide over the wire perfectly. I then used liquid weld to epoxy it to the cross brace. Now it's snug without any wobble. About the Z bendings. I have two Z bend tools and both failed to bend the harder and brittle pushrod wire so it would fit my JR control horns. I used Dubro pushrods which worked very well.

jpjamie

I had the same idea and used a carbon fiber tube instead of brass or aluminum over the tail wheel wire epoxied to a cross brace epoxied to the bulkhead and it works great.

bradyb

I pulled it off yesterday with a brass tube and an additional cross brace, the only issue now is that the plane in more tail heavy then ever. I put the receiver batt in the slot infront of the wing mount and below the fuel tank and it still balanced at about 5". I'm now going to try and and mount the battery under the engine mount box where the ignition box would go and see if that works.

I did weigh it yesterday with everything mounted, JR high torque/digital servos and recommended retract servos, 6 channel 2.4 spektrum receiver, SAIT0 125, and the long header pipe and it appears to weigh in at about 10 pounds. The low weight would explain the problem of being so nose-light.

Spitpilot

My Feedback: (12)

Just finished up my Blue Nose - I have been following this thread for a while and like most have had similar issues so thought I would summarize my build;
1) Like everyone else I had to beef up the retract rails and attachment - used glass cloth and resin liberally to areas I could reach and added angle blocks to reinforce rib to spar and skin structure. 2) Replaced the cowl captive nuts with 'Well' nuts which have a rubber flange which helps damp out vibration and makes the cowl fit a little better. 3) I am using a Saito 125 with a Keleo Pitts muffler - cut back the tubes by about an inch to reduce the amount exposed below the cowl. 4) I also am using the Pacific Scaled Aircraft exhaust and thier flush air filter cover kit. 5) I checked the wing wash out and have 1-1 1/2 degrees of wash out on both wings. (unlike my H9 150 P51 which has about 1 1/2 degrees of wash out on one wing and about 1 degree of wash in, really bad on the other wing and as yet still have not flown it like this) 6) I ran the engine on a stand for 3 tank fulls before trying it in the airplane - the vibration levels are quite acceptable with the balance plastic spinner but as you can see in the photos I am using a 4" Dave Brown aluminum spinner. 7) I intend to fly without the two canopy attachment screws and rely on the magnetic catches only - I think this will be ok but will see after the first flight. 8) I am using a 6v 1700 mAh RX battery and a 1.2 v 1900 mAh battery for the C-Tronics glow driver. 9) I have a 1/8" gap between the wing leading edge and the fuse recess which no one else in the thread has mentioned but will leave this for now. 10) I have yet to address the wobbly tail wheel but will do this before first flight. 11) The CG came out at 4.7" without adding weight to the nose or tail but the weight is at 11.5# driving the wing loading up to about 35oz/sq ft which does concern me a bit. I think the CG at 4.7", 26% MAC is nose heavy although reports in FLY RC mag say it should be fine - we shall see.
In general I think the quality of this ARF is ok but more attention to detail in critical areas like the retract rail attachment, tail wheel support and wood quality would produce a really good model at no or little cost increase - better quality control and oversight of the Chinese manufacturer by the people at H9 would fix these issues we all have struggle with.

RodanAZ

I would NOT fly it without the canopy bolts. I think you'd be surprised how much air is going into the fuselage. I can't tell from your pics if you opened the radiator outlet, but even with it open, you'll have positive pressure in the fuse. On my 50cc Extra, I had one of two canopy screw come loose, and the pressure blew the canopy off, breaking some of the ply structure.

Since it appears you can't buy the canopy/hatch separately from HH, it would be a shame to damage it....

Pit-Viper 1

My Feedback: (12)

It's an easy fix for the gap in the leading as well. What I do is use 30min epoxy, alcohol, and micro balloons. I mix up 2 separate batches of epoxy and micro balloons, about 1/2oz. of epoxy in each cup, then add the micro balloons and mix it until it gets to about the texture of toothpaste. The cup will fill up fast when you start adding the balloons, works better if you use a plastic cup.Use the alcohol to thin if needed but very sparingly as it doesn't take much. Cover the wing with wax paper where it contacts the wing saddle or where repairs are going to be. Now just add the mixture to the area needed, don't worry about getting too much. You want enough so that when you attach the wing it will fill the gap. If it's going to be around the wing dowls I apply vasoline to them so the epoxy won't stick and the vasoline won't soak into the wood. Now attach the wing and let it sit for about 20-30min then remove wing and you should still be able to remove the excess with a hobby knife. You can pull the covering back if you like so that it makes contact with the wood. Also I put blue painters tape on the outside of the fuse along the wing saddle to make cleanup easier. Once it cures you'll have a perfectly fitting wing with no gaps. I do this on all my planes, it's easier if your building because you don't have to worry about the covering or gear getting epoxy on them.

Shane

Pit-Viper 1

My Feedback: (12)

Oh yeah try to get all the wrinkles out of the wax paper where it will contact the the epoxy.

Shane

charlie1960

The hatch WILL blow off.......

luckily it landed almost at my feet.

Spitpilot

My Feedback: (12)

Thanks for your input RodanAZ - I understand your concern but since I only intend to use the Saito 125 I do not need the cooling flow in the fuse as required for an electric set up. The two large diameter cooling holes in the firewall and other small potential leaks have been sealed off to keep any leaking fuel out so the fuse will not be pressurized. Although I do not have the radiator outlet installed it might be advantageous for me to do so as this would create negative pressure in the fuse and add to the magnetic forces holding the canopy section in place. This being said, and considering the potential damage and loss of the canopy section, I may just use the retention screws to ensure loss of the canopy section does not occur.

RodanAZ

I've been intending to build a spring loaded latch for the canopy, just can't seem to find time. The canopy bolts are one more little annoyance with this plane, and it just makes you wonder what they were thinking?

"Hey, lets make a nice big hatch for the electric folks, then use two bolts to hold it on to prevent any kind of quick and easy access..."

bradyb

Please help guys.

I’m still nose heavy with the 2400 receiver batt mounted underneath the engine mount box. It’s kind of making me angry that I built the plane exactly as instructed and it’s so tail heavy. With an additional 4 ounces up in the cowl I’m balancing just beyond 5�. Am I getting my wires crossed, I’m measuring back from the leading edge of the wing and additional nose weight should move the cg forward, correct?

Here’s a question, I’m going to add a full tank of fuel that will obviously move the CG forward. What do you electric guys do when you build the plane to a recommended CG that was adjusted back for a full tank of fuel? Obviously the plane needs to fly when it is almost out of fuel but is that the optimum cg? Did H9 take that into account when they designed the plane and that’s why someone who is running a lighter weight engine like the SAITO 125 would have a problem balancing the plane? Maybe the nitro/gas CG is 5� and the electric is 4.5�?

It’s kind of ridiculous but have I indeed built a .60-sized airplane with a big SAITO 125 that is really tail heavy.

What’s worse, having to balance the plane with an additional 8-12 ounces in the nose for a total weight of about 11.25 pounds or a CG that is 5� back?

CRG

My Feedback: (3)

Centers of Gravity are rarely if ever 'adjusted back' for full fuel. Balancing should be done without fuel, the recommended CG assumes this 'worst case' condition. With full fuel you are just slightly nose heavy.

bradyb

I was really hoping I could build a super fast hot rod with out ridiculous wing loading. I really hate dead weight. Any ideas for how to add more weight up front? What is a good size for an on board glow plug battery? I’ve already got the remote glow plug hooked up, it would be easy to add in a switch and have the option to use the on board battery or a fresh external battery.

I’m getting the super-awesome exhaust kit, I don’t assume that will add much weight though.

Any ideas?

charlie1960

I cant understand your problem with balancing the A/C. I balanced at 4.5 with a saito 100 and the 5 cell, 6 volt RX batter mounted on top of the engine box right behind the engine under the top of the cowl. And the 1.00 is appx 4.5 ounces lighter than the 1.25
And that was ready to fly minus fuel.
Could there be that much difference in the dry shipped weights of these planes?
BTW, she now sports a 1.25

82blackbird

My Feedback: (3)

OK, you lost me with the first two sentences??????????????????

bradyb

Sorry. Essentially the plane needs an additional 8ozs of weight in the nose and I don't know why. Even with the receiver battery mounted under the engine mount box (the same location the manual suggested to mount the ignition box).

charlie1960

Surely has me stumped...[:-]

bradyb

Charlie, how much does your plane weigh. Before additional weight, mine was 10.5 pounds.

I added metal clevises for the elevator pushrods, and a very small piece of ply to strengthen the stupid tail gear. I wonder if someone in China accidentally emptied a bottle of glue into the tail somewhere.

I did not install the cockpit plastics, or the canopy hatch bolts after I noticed how tail-heavy the plane was. I will be sealing up the firewall with a thin piece of ply to keep the oil out of the fuse and prevent the fuse from becoming pressurized.

The landing gear being up or down, makes no difference with the CG, correct?

charlie1960

Gear up.
I never weighed the plane as i have no scales.
Just guessing, id say 10 to 10.5. it feels heavy. I know its heavier than my last Mustang.WM Petie 2nd
How much ply did you add to the tail?
I didnt install the cockpit junk either. I like the clean look better.

bradyb

A double stack of 1/8" ply .25x2.5" with a touch of epoxy, nothing substancial.

I hate to over load the plane but the alternative would be to wait for a few months while Horizon sends me a new kit?

charlie1960

Lets.......start at the beginning. Is your balancing stand set correctly? I only ask because Ive misread mine a couple of times.
and it drove me to the edge before i finaly realized what was happening.

bradyb

My balancing stand consists of my finger tips. I'm apologize but how would a balancing stand make much difference, is that really something I need to pay for? The one I have now is way too small.

Please wait while I put on my condemnation slicker...

bradyb

I called Horizon, they are going to send an email to H9 asking what I should do. They’ll probably suggest that I add the required weight as long as I keep the plane at less then 11 pounds. That’s really disappointing, the Saito 125 (24.69oz) actually weighs less then the Evo .61 (25.44oz) but it will require about 8oz to balance.

You know what’s hilarious, the flying weight is listed at 9.5-11 pounds at Horizon. How in the hay would you build this plane at 9.5 Ibs? You would have to install a .52 engine, set up the plane up as a three channel, use fixed gear, and glue on the flaps.

Spitpilot

My Feedback: (12)

Mine weighs in at 11.5 #, using a Saito 125, 6v 1700 mAh RX battery just behind the fuel tank and a 1.2 v 1900 mAh glow driver battery a little further aft, no added weight in the nose or tail to balance at 4.7" from wing LE at the body - what is happening to get your CG so far off with all the added weight? I agree, how do you end up with the quoted weight by H9 of 9.5 - 10 # with engines in the Saito 100 or 125 class.

Pit-Viper 1

My Feedback: (12)

bradyb,

Just a suggestion. I've had to add a lot of weight like this before. 7 1/2oz. I believe it was. What I ended up doing was add stick on weights right to the engine mount as far forward as I could get them. This cut the weight down almost half. It's in the cowl so you don't see it. I've even melted weight inside the end of a spinner although I wouldn't suggest that, it was a pain to get the spinner balanced afterwards. I just glue them together them roughen up the mount as much as possible and glue them on. The zip tie is added insurance.

I got one question, you are balancing it upside down right? I did this on my first plane which was the H9 PTS P-51 and could not figure out what was wrong.


Shane