Futterama

I must admit I have also thought of why the fuel tank wasn't at CG on our models, especially those with gas engines, which have a carb that can easily suck up the fuel from afar.

sjhanc, I have just received my plane yesterday and is eager to see your installation of the fuel tank at CG - do you have any pictures to show us?

radfordc

My Feedback: (14)

I haven't noticed an inherent nose over problem with my warbirds, but I'm landing with most of the fuel gone so the CG is back to "normal".

sjhanc

My Feedback: (3)

The first 2 pictures show the H 9 tank location. The tank CG is the black line just in front of the velcro strap. The model's CG with the wing off is the black line across the wing root fairing. After I get a final CG set I aways remove the wing and hang the fuse from the wing fairings to get a wing-off CG that can easily be checked when moving equipment around. Since the wing's equipment is almost never changed this makes future balance checks easy, just lift the fuse with a finger on each side under the marks to check CG. This CG check is usually not needed with gas powered models unless changing an engine is done.

I have several electric powered models that have different lipo battery packs so a CG check is required for each different weight battery. My lipo packs range from 4-7 lbs and a drastic CG change is the result. I use a unique foam spacer block for each pack to automatically get the correct CG. One foam block is labeled for (4) six cell lipo packs and another is labeled for (6) four cell lipo packs.

The third picture shows the tank installation of my TF GS ARF P-51B, It is barely visible hung under the plywood shelf towards the front of the wing area. In this case the wing-off CG is denoted by the red line across the wing saddles.

sjhanc

My Feedback: (3)

Also because this particular H 9 P-51 was tail heavy with the recommended equipment installation compared to the first H-9 P-51 that I built last year, I had to jump through hoops to get it to balance without 1.5 lbs. of lead in the nose (at the spinner backplate). The elevator servos were moved from the stabs up to the tank compartment (forcing the tank to move about 1.5 inchs forward). The steel hinge rods were scrapped and replaced with carbon fiber rods from Tower Hobbies and the smallest possible tail wheel was installed. I left off the tail wheel doors to save more weight and had to move the throttle servo back beside the rudder and tail wheel steering servos. To avoid adding more weight behind the CG a digital wing servo was used for throttle. The 10 cell nicad receiver battery was changed to two individual 5 cell packs strapped to the back of the firewall, its original location was to be beside the fuel tank at the bottom of the tank picture. The heavy nicad cells were chosen to help balance the plane and their considerable weight did help, plus giving me over 5200 mah receiver batt. capacity. A 2100 mah NimH ignition pack is mounted with the ign. module in the compartment in front of the wing dowels.

The end result is a DA 60 powered model that weighs 27lbs 5 oz. plus fuel and is THE BEST flying P-51 I have ever had my hands on. Radio is JR XG14 with XBUS servo wiring. Retracts are Robart air powered that I modified for reliable retraction cycles by changing the air cylinders and the linkage. Also, you can't see it in the pictures but the gear door servos were moved to the cavity in front of the wheels to make room for the fuel tank. Their linkage is connected to the front of the gear doors and goes over center at the servo arm when closed to prevent air loads from pulling the doors open in flight. I have used this door servo installation twice with excellent results but the retract gear modification was not perfected until the first plane had 40 flights on it. The gear modification worked perfectly until the left flap servo failed in the down position on a landing approach at about the 50th flight. Its excessive travel to 90 degrees down forced the plane into a slow descending left turn into the trees and a lot of cosmetic damage forced me to scrap it and use it for parts. I have since changed the flap servos for very high torque digital landing gear servos, also with an over-center linkage in the full-flaps-down position. Some aluminum servo arms (for RC race trucks) complete the flap linkage and are absolutely rigid, up or down. To slow this clean airframe down for landing the full-down flap travel was increased to 50 degrees. This setting produces much more drag and less lift and the plane's tendency to float past the touchdown point has been eliminated. Nice level approaches at slow speed are the result with the right amount of throttle on.

I got suspicious when I noticed a pattern of flap servo failures over several years. I had rigged the flap linkage for the servo arm to go over center when flaps were up, thinking that this would prevent flutter at high speeds. The fact was that the flap servos were under heavy aerodynamic loads when flaps were down full, fighting the prop blast for as long as 30 seconds during an approach. A couple of flap servos just died but one began pulling very high current and smoking even though it still worked properly. The fix for this was to change the flap linkage so that the servo load decreased as the flap's down angle increased, going over-center at the servo arm at full flaps. This meant no load at all on the servo at full flaps down. To keep the no-flutter-at-high-speeds safety factor the flap servos were changed to very-high-torque mechanical gear servos (digital proportional).

sjhanc

My Feedback: (3)

radfordc,
I also used to fly with the smallest tank I needed for 10 minute and 2 minutes for go round landing attempts. I have had several close calls with running out of fuel after the runway was closed due to a crash or, more likely, a ground loop and nose-over followed by the guilty pilot slowly walking out to assess his plane, gather it all up then drag a*s back to the pits with the wreckage while my plane slowly orbited, trying to stretch the fuel until the runway is opened again. I installed much larger tanks in my planes for almost unlimited reserve if it was needed.

At almost every event I attend something like this happens but I don't have to sweat it out-If I have flown most of my usual 10 minute flight I can throttle way back and orbit for 20 minutes at very low fuel draw until the runway is opened. The worst thing that happened last year during a gaggle flight was one warbird noseing over, then another running out of fuel while waiting for the first plane to be recovered, then the third pilot declaring a fuel emergency followed by a good deadstick landing between the other two downed planes and the recovery people. I cruised my plane around while the announcer remarked about the amazing duration the last Mustang seemed to have. They finally got it all cleaned up except that the golf cart with the second plane and pilot on board started to travel down the runway back to the pits instead of driving over to the side of the runway to let me land my plane. I set up my landing approach anyway and I think that the pilot sitting backwards holding his plane on the golf cart noticed my plane turning final, and said something to the driver, who began a slow turn towards the edge. I continued my approach but kept it high waiting for them to clear out and when I reached the runway, it was too high to make a landing. This particular club's runway is smooth grass but has a slope at each end and a fence at the west end up the slope a ways. Long landing runouts to the west are not an option, so I added a little power and did a low altitude go-round and got it down for a nice on-the-mains landing. I removed the wing to see how much fuel was left and found about 4 oz. I probably wouldn't have been able to use all of it, there is always some fuel that can't by pulled out.

I had started my action cam at the time I taxiied out for takeoff and the total video time back to the pits after the extended flight was 24 minutes. Since I usually use 12-14 oz. for a ten minute at high speed that left 18-20 oz. (out of 32 oz. capacity) for the orbiting part and the gear down-flaps down part lasted about 5-6 minutes through 3 approaches.

But I was able to land with a running engine so the larger tank made my day on that occasion. Before I installed the big tank I have had the engine stop, out of fuel at the end of the landing roll several times and it went deadstick several times on final with damage on a couple of short landings. My TF GS P-51B glides like a brick-with-fins deadstick but my heavier H 9 P-51D doesn't seem to notice the prop has stopped and will glide from the downwind all the way around a 180 degree turn back to the runway, even with the gear and takeoff flaps down.

AC2

My Feedback: (34)

Sj,

I appreciate the extra information you throw in....good stuff

ADKer

I got around to a couple radar runs on the EME 60/Falcon 23x10 and top was 118 mph no wind level flight. For all around performance I really like this setup and it performs great in the air!

Stevedavy

After what seems an age I finally maidened my P51 converted to electric, he flies on rails I'm really happy with Gentleman Jim.



Steve Davy

ADKer

Nice! Is that a Biela prop?

Stevedavy

Yeah it's a 23x10

BUDMAN27

Should I drill some holes in the air scoop for the carb to breath ?

sjhanc

My Feedback: (3)

I took my Mustang to the OTOW event today. Fair attendance, around 30 pilots and some had several planes. I thought, from the weather forecast, that it would be windy and cold. It was cold, low 40s, but very clear and little wind at first. I got set up for an early flight to beat the gusty wind coming later. On my 1st flight it went well until I completed a high speed pass, then I noticed 1 gear door hanging down so I cut throttle and brought it in for a good landing, not wanting to risk losing the door. It took Bill and I a half hour to fix the horn that had come loose from the door. I had to reinforce the cracked plastic near the horn slot with a thin piece of hardwood I scrounged from the tool box. That done, I checked the plane all over and noticed that the black oil residue the DA 60 had been spraying back on the belly scoop had changed to red unburned Redline oil, always a good sign with a new engine. Last week it had started idling too high and running rich from 1/2 throttle up so I had tweeked the needles a tiny amount, and today it began to prop rip, something this new motor had not done before during the previous 20 flights.

Turning a Graupner 22-12 PRO carbon prop fast enough to rip in level flight takes some serious horspower. I may be able to run a larger prop soon. The next 2 flights went very well inspite of the occasional gusty winds blowing though. While the landings were not the best I have done, none were messed up, we had a good day.

piwie

Hello,
can anybody help me? I come from Germany and had buy a P51 from Hangar 9 60cc last week .
I want to buy the spinner from Dave Brown and spray it with the Colors like the HAN Spinner. Did anyone knows the RAL Colors red and yellow?
The wheels comes also from HAN . The Diameter is 5-1/4". Is there anyone who knows the with of the wheels?
It is yery difficult to get the addional parts for the Hangar 9 P512 in Europe. The retracts from Eflite come from US but they do not sold them to Germany.

Thanks
Frank

BobH

My Feedback: (2)

The red is Insignia Red and the Yellow is Recognition Yellow

sjhanc

My Feedback: (3)

The Dave Brown spinner is 5 1/2 inch diameter and the red color is listed in the manual that comes with the plane on page 11. Just buy the Hanger 9 aerosol spray can "Deep Red" and "Cub Yellow" color paint. To paint the spinner I mount the spinner on an electric hand drill using old engine prop adapter parts and spin it while spraying the paint from a distance to allow the paint to dry a little before reaching the spinner. Apply very thin coats of paint, don't try to get an opaque color right away. Let the paint dry to the touch between coats. If the paint is applied wet it will run. Be sure to clean the spinner surface with thinner or acetone and don't touch the surface before applying paint. I use fine steel wool (1000) to rough the surface so the paint will adhere. The full scale spinners were painted with silver paint for delivery then Group colors were applied in the field. They may have removed the original silver in some cases. Look at the reflectivity of the full scale plane, a high shine (transparent red) indicates the paint was applied over polished metal, a duller finish indicates the paint was sprayed over the silver base coat.

Be sure to balance the spinner and back plate, do the backplate first, then add the cone and balance again. I use strips of Gorilla brand duct tape (black) applied to the inside of the cone for balance weight. It is tenacious and won't fall off. I have a giant scale electric powered warbird, I take the prop off, install the painted spinner with a dummy prop hub (balanced), then run the electric motor up to check vibration levels of the balanced spinner. An index mark across the backplate and cone makes balancing easier. I adjust the throttle until any dynamic vibration is maximised and apply a magic marker (erasable) to the middle of the cone. Bring the marker slowly in to the spinning assembly 1/2 way from the backplate to the tip, trying to barely touch the turning cone with the marker. If there is a lot of vibration the marks will be short and dark (apply tape inside-opposite the marks). If the spinner is finally in balance the marks will be random and long and thin. Some new spinners don't need balance weight and some do. A large spinner that has visible vibration will not last long. My electric motor will turn a spinner (without a prop) over 8,000 rpm. If the spinner vibrates, the top rpm will be as much as 500 rpm less, and the plane will shake. DO NOT GET BODY PARTS IN THE PLANE OF ROTATION, a failure can cause serious injury.

piwie

Hello,

thanks for the very quick and detail Information.
The spinner from Dave Brown 5-1/2" diameter , do you know the length from it? Or otherwise the lenght from the original Spinner from Hangar 9?

Frank

sjhanc

My Feedback: (3)

The length is 5.5 inches and the diameter is 5.5 inches. I don't personally know of anyone who bought the expensive painted spinner from Horizon, but you can buy an anodised spinner from Tru-Turn in red, then you can mask it and paint the yellow stripe yourself. Tru -Turn spinners don't usually need balancing, but check it to be sure. I use both brands and get excellent performance. The 2 manufacturers use different production methods with Dave brown spinners coming out cheaper but sometimes needing final balancing.

sjhanc

My Feedback: (3)

I attended the Ocala "Salute to Veterans" event yesterday. the weather started out cool and clear with winds down the runway at 5-8 mph. My first flight ended up getting delayed with retract air lines popping off twice in the hot sun. Once I got that fixed my flight went off pretty good with a landing that bounced slightly but no problem getting it to settle down on the mains for most of the runout. By the time I got the Mustang serviced and ready for the next flight the wind had begun to pick up to 15 gusting to 20 mph and the club closed the runway for the demo flights to go on. The wind kept increasing to 20-25 gusting over 30 mph at times so most of the pilots elected to wait it out. After the demo flights were over only a couple of jets were flying. I sensed that the wind might be slacking off so I launched my plane. In the air I ran into a lot of turbulence below 75 feet so I stayed high through most of the flight. I usually land at 10 minutes but the wind increased to 30 gusting higher so I throttled back to save fuel and wait for less wind. A thermal passed and the wind dropped off so I set up for a landing. At that time the wind came back up to 20 mph and swung to 20 degrees left crosswind. I bit the bullet, turned onto the downwind leg much higher than my usual 75 feet, dropped the gear and full flaps, put the nose down for a steep descent and a continuous turn back to the runway. It came over the trees high, diving for the runway at 1/2 throttle and it somehow all came together with a lot of right rudder for the crosswind and the left wing down to stop the drift. At about 3 feet I throttled back and flew it down to the touchdown, leveling the wings as the wheels touched. I was expecting a bounce like the first landing but it stuck and ran the whole length of the runway with the tail up and me slowly reducing power. It ran off the end into the grass but the strong head wind had slowed the ground speed considerably so the tail came down and the plane slowed quickly in the grass. Once stopped I let it sit there while I took a breath, then turned it right to taxi across to the pit side. As I turned it back west the wind gusted again and it was pushed along at idle back towards me. I was fearing an out-of-control nose over so I killed the engine and as it stopped I turned it right into the wind. We walked out to get it with the wind blasting, I was afraid a gust might blow it over. I dragged it back and and another pilot decided that if I could fly that wind, he could too. He launched his TF GS Mustang into the gale, fought the turbulence for a couple of minutes, then landed very long and decided to taxi all the way back. He was almost back when it suddenly nosed over, breaking the prop. I put my plane in the van for the trip home.

NICKELUP

My Feedback: (82)

Hi I am looking for the cockpit, and horizon doesn't carry it anymore. Does anyone know where I can get a replacement for it? Thank you

box55555

My set up works as yours, except the tailwheel goes the wrong way. Do you just reverse the two wires in the plug?

Len Todd

Yep!

TXKflier

Never mind..

Ham639

My Feedback: (13)

Here's my H9 'Stang.

Striped it, glassed it and paint. All the silvers (4 of them) are rattle cans, the rest is model masters.

Robart Gear, DLE 55. Great flyer.

I typically build all my projects but I had a little free time, so I did this to teach the local guys they could make an ARF their own with a little extra time involved.

I have about 60 hours in this. Good airplane with about the best outline out there for an affordable P-51!

Ham639

ADKer

WOW! Looks great!

marksp

My Feedback: (9)

Brilliant!