syamaner

I will try to share my experience on an ESM Sea Fury with you.
Sea Fury is one of my favorite aircraft for more than three years. My first Sea Fury was manufactured by Seagull. It has been flying for more than 3 years first with a Thunder Tiger 130 FS engine and then with a DLE 20. After these three years with this lovely warbird I decided to put a larger one together. Here in Istanbul we have not much choices for a warbird. There was a Black Horse Sea Fury and an ESM Sea Fury. I decided for the latter because I thought it would be harder (!) to fly. I think I needed some more adrenaline!
The ESM Sea Fury has a wingspan of 203 cm and a proposed flying weight of 8.1 kg. It shall fly with a 30 or 40 cc gasser.
A short internet search provided me with a lot of information. For example there was nobody who had been able finish this bird under 10 kg. Another information was that the ESM aircraft are almost always tail heavy requiring a lot of ballast to the firewall. Most of the modellers have used around 1 - 1.5 kg ballast to be able to achieve an acceptable CG. As the aircraft has a relatively wide front section, I decided to use a 50 - 55 cc engine so that some of the required ballast would be a power producing piece of metal. Due to the very satisfactory records of DLE engines in my own and my friends’ aircraft I decided to use a DLE 55 engine.
ESM aircraft assembly manuals are known by their extreme details (!). For example the setup of the pull pull elevator linkage (me and my friends had a long discussion about it for a week or so) was shown in a single drawing. But this didn’t prevent me from studying the manual for a couple of weeks before beginnig the assembly.
As always I started with the wing. The wing has a center section containing the inboard part of the split flaps and the retracts. The outer panels contain the ailerons and outboard flaps. The two parts of the flaps are being joined by a 0.8 mm wire and controlled by a servo in the outer wing panel. Ailerons were hinged using CA hinges (but not ones which came with the kit) and flaps were hinged with pinned hinges secured with epoxy glue. All steps here were straightforward without any difficulties. I used electric retracts from ESM. One of the positive points was that the aircraft had a sheet of epoxy based plate between the sheets of the plywood in the gear mount. This will probably add extra strength to the gear mounts.
Unfortunately the plastic parts designed as wheel wells are of a very low quality. To be able to access the servo connections in the future I decided not to glue the wheel wells. I used wood screws instead.
Another positive point of the aircraft is the design of the gear mounts. They are placed so that the wheels extend well ahead of the leading edge of the aircraft thus preventing unintentional nose overs during take off and landing.

To be continued...

syamaner

After gluing the wing panels to the center section using the two (at each side) wood joiners the wing was almost ready.
Unfortunately the fuselage was not such straightforward. The elevators (two separate elevator tabs at each side) are designed to use a special metal piece as a joiner and as a pull pull horn. I have read some posts about the safety of this system. First, with time the U wire gets lose in the elevator tabs which leads to assymetry and flutter. Second, the weld joining the U wire with the horn can separate and this uneviteably would lead to a crash. Most important point is, after the assembly you don’t have the opportunity to regularly check this part because it will be hidden inside the vertical stab forever.
My first decision was to use separate horns for the two elevators. One option was to place two elevator servos to the tail of the aircraft but given the tail heavy structure this was not a good choice. So I needed to use one or two long (around 110 cm) pushrods. This solution seemed neither good. So I used 4 mm * 2 mm hollow carbon rods and glued pushrods to both ends. I used two separate elevator servos mounted on the main servo tray in the front part of the aircraft. To prevent the flex of the carbon rods I glued a pushrod guide to the first accessible former which perfectly prevented the flexing of the rods.
Rudder and tailwheel are connected to a single servo with separate pull pull wires. The tailwheel assembly was designed to be glued to the rear former but I decided to use a small wood plate between the assembly and the former so that the horn would have a better clearance.
Every step has been checked and approved by our certified technician!

syamaner

After the engine and tank has been prepared and mounted to the aircraft, it was almost ready to go to the field. The size was impressive (at least for me)! There was a little problem with the spinner. I have used a 4.25 inches spinner which had an M6 screw but the thread size of the DLE55 shaft was M5. An M5 screw would lead to the risk of imbalance because the head would be too small for the spinner. So I took an M6 screw and converted it to M5 at the threaded end. Test fitting of the cowling and mounting the canopy were easy steps.
The aircraft has been transported to the field by one of my friends because I couldn’t fit the aircraft in my car. At the field we first checked the weight and it was around 9.5 kg. But when we checked the CG we found out that we needed 1.3 kg ballast at the firewall level. This was achieved using a plasma cut piece of iron bolted to the firewall.

syamaner

Now the aircraft was ready to fly. The engine had been already broken in several weeks ago. But what about the pilot? Was he ready???
The take off weight of the aircraft was around 11 kg and with a wing area of around 77 dm2 the wing loading was 150 g/dm2 and this was way too high! The previous Sea Fury (Seagull) had a wing loading of 110 g/dm2. All this data made the pilot (it’s me!) to create reasons for not making the maiden flight. But how long could I invent problems to prevent the first flight?
At the end, I couldn’t resist the pressure and decided to fly the aircraft for the first time. Everything has been triple checked. Then we shot a group photo with the aircraft and you can see the rest in the video!

http://www.youtube.com/watch?v=HKu61wjavRg

syamaner

I have read many comments about this aircraft where the builders said that “the plane flies like a charm”. Yes this was true! It is rock solid in the air (remember the 150 g/dm2 wing loading). DLE55 is just right for this aircraft. Using a 22 x 10 prop it performs very well. First I was afraid for the turns because I didn’t know the handling characteristic of the aircraft but I found out that this is a very nice flying bird witout any bad habits. Even during sharp turns with a lot of roll it flies well. In contrast to it’s predecessor, the Seagull Sea Fury which had a marked tendency to balloon with flaps, this aircraft shows almost no pitch change during deployment of the flaps (partial or full). I think the servo slowing function of the Aurora plays a role in this aspect because I have slowed down the flap channels to 2 seconds.
As the maiden flight was not bad I started to look for further info and found the concept of “cubic wing loading”. This is something different than the classical wing loading and it leads to a better prediction of an aircrafts flying characteristic. The cubic wing loading can be calculated by weight squared / wing area ^3. For this particular aircraft it is 17. The older Sea Fury has a cubic wing loading of 15. This can explain why I could fly the aircraft without too much difficulty although it had a wing loading of 150 g/dm2.

irocbsa

My Feedback: (12)

Nice work and congrats on the maiden.

mick15

Can I suggest you need a lot more landing flap deflection to assist in slowing the model for touch down.

m

syamaner

Thank you "irocbsa" and "mick 15".
I made the first landing with the take off flap setting (maybe 10 - 15 degrees). Due to sidewind I elected not to use full flap. But I fully agree with you.

mick15

I can show you a video of mine if you wish, like the full size I use 85degrees of landing flap. It does show a very docile landing approach even with a 36Kg model.

m


http://www.youtube.com/watch?v=PcayN...&feature=share

syamaner

It would be a pleasure to watch your video.
During my PPL lessons we have been taught not to use flaps with excessive sidewinds. But with my old Sea Fury I had noticed that in any weather condition dropping full flaps stabilizes the aircraft significantly. My standart landing begins with power reduction on downwind followed by first notch of flaps and when turning to final I drop full flaps. As I wasn't familiar with the new aircraft I decided not to use full flaps (with the sidewind component in mind).
With 85 degrees of landing flaps I think you need significant power all the way down until the last couple of inches. Right?

aghost

My Feedback: (13)

Congrats on the maiden. Looks like the DLE55 pulls it around well.


Brian

syamaner

Thanks Brian. DLE55 seems to be a good choice.
Mick15 it is a masterpiece. Great! Thank you for the video and advice.

mick15

Thanks for the compliment, I hoped the video would demonstrate the outcome of landings with different flap settings, you can clearly see the half flap landings are much faster and longer than the full flap ones. The idea is to create a large amount of drag and keep the model flying with throttle, in the video I'm on 10-12%, remember throttle is distance, elevator is speed.

Happy landings.

m

syamaner

Now a couple of flight videos... Landing flaps has been adjusted for full travel to mechanical limits. This has a marked stabilizing effect on the final approach.

http://www.youtube.com/watch?feature=player_embedded&v=OX2Tu7QPoS4 http://www.youtube.com/watch?feature=player_embedded&v=6oA6BuuAPzw http://www.youtube.com/watch?feature=player_embedded&v=zzEfOrbaa8o

syamaner

I had problems with one retract. It would bind anywhere during its travel and stop. A detailed examination showed a bent jackscrew. During tests I inadvertently connected the retract to a servo tester and burnt the motor. After replacing the motor and correcting the jackscrew everything worked fine. As the replacement motor is not the same as the original (I could find a FK-130SH motor but there are no data about the original motor) the two retracts have different speeds which leads to a more realistic appearance.

Sporter83

Hi, would you happen to have the manual for this plane still at all? Thanks Steve

syamaner

Will check it and if I can find it I will let you know.

Sporter83

I’m really only after some throws & cog but yeah if you had the manual that would be awesome. Thank you

syamaner

Here...
https://www.dropbox.com/s/hi5urt10an...80FAF.pdf?dl=0

Sporter83

G’day guys. So I have decided to go the Saito FG-60R3. My question is, do I just bolt it to the firewall with the supplied stand-offs or will it have to have right/left-up-down trust built in somehow? Thanks Steve