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        Cool Hokusei Ultima EPP BX * * The most feral 3D EPP plane in its class * * NEW VIDEOS!

#1 groovejet Mar 30, 2009 03:17 AM

Hokusei Ultima EPP BX * * The most feral 3D EPP plane in its class * * NEW VIDEOS!
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I've known for quite a few months that this plane has amazing capabilities.

I have more than 20 planes and this one has been in my top 3 for some time. What I have decided in the past week is that this is now my favourite plane.

It's just magic! It's a full-on feral animal of a 3D foamy, and is more savage than a Tassie Devil http://yadogg.com/wp-content/uploads...nian-devil.jpg ;).

I've tried just about every good EPP 3D kit available, and I simply have not found another plane with such wild and dynamic abilities. Its control surfaces are extremely responsive which allows it to do blindingly quick snaps and spins, and ridiculously brutal tumbles and blenders. Spectators are regularly astonished and awe-struck when watching this plane. When you're not in the mood for such dramatic performances, it's well mannered enough to cruise around sedately in a relaxing fashion.

Everyone with an interest in 3D foamies should have one!

Not convinced? Check out these videos !!

Hokusei Ultima BX - Love That Plane ................ http://www.rcgroups.com/forums/showp...5&postcount=38
Flight of the Ultima BX - Complete and Uncut .... http://www.rcgroups.com/forums/showp...3&postcount=51

If you like what you see and wish to have your own Hokusei Ultima BX fun, visit www.bestvaluerc.com and buy one!

#2 groovejet Mar 30, 2009 06:28 AM

I couldn't resist
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I have a new EPP plane to try! It's a Hokusei Ultima EPP BX and appears to be a new design by the respected Japanese manufacturer Hokusei that is based on the Ultima SOV.

I bought 2 Ultima BX kits from www.bestvaluerc.com in China. This is a new website operated by the owner of www.wattaplane.com, which is where I bought all of my previous Hokusei planes from. wattaplane is still active but bestvaluerc has a few advantages. It offers planes from several manufacturers, so for example you can mix TechOne planes and Hokusei planes in a single order. bestvaluerc has more postage options that can reduce the postage cost considerably.

Here's a link to the plane on the Hokusei website: http://www.hokusei-japan.com/product...ma-epp-bx.html Scroll down to see photos and video links. The first video features some impressive flying and shows that this plane can do fantastic rolling harriers.

I've studied web photos and videos of the Ultima SOV and Ultima BX and I've noticed some differences. The Ultima BX is smaller and lighter. It has a very tall fuselage that I expect will make it a fantastic knife edging plane. It appears to have a relatively short fuselage but this might be an illusion caused by the tall fuselage as when I placed the fuselage and rudder beside the wing they looked about the same length. Looking at the design of the plane I suspect that it'll be more of a pattern 3D plane like the Hokusei Primus Z, but I've been surprised a few times by the characteristics of some planes that weren't obvious just by studying the airframe design.

Unlike the Primus Z, the Ultima BX has a flat plate foam sheet on the bottom of the fuselage. I suspect this is what the BX in its name indicates. All the BX planes on the Hokusei site have this feature. Does this make a difference? Well I believe it leads to a fuselage that is more resistant to tail twist. The planes that I own with a flat plate on the bottom of the fuselage definately twist less than those I own without it, though I don't have many planes without it so it might be related to other design aspects.

Here are a few photos to get things started. I'll post more photos once I start the build.

EDIT: I've started the build.

I've glued the main wing on but I haven't attached the ailerons yet. I've also glued the horizontal stabiliser on and hinged the elevator. So far this kit is building in the traditional Hokusei way, so it should be a simple and fast build.

The control surfaces consist of a thin layer of Depron sandwiched between sheets of EPP. In the areas where the CA hinges are placed there is no Depron. Be careful when gluing in the hinges that you don't let your CA run too far or it will eat the Depron a little. Consider using foam safe CA instead if you're worried about this.

This combination of Depron sandwiched between EPP has proven to be very durable on my other Hokusei kits. It seems to have the durability of straight EPP but benefits from the stiffness of Derpon within. CF is still used in appropraite areas for extra rigidity.

Here are some progress photos. I forgot to take a photo of the very tall fuselage. Maybe next time.

#3 groovejet Mar 31, 2009 05:21 AM

More progress
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Tonight I attached the ailerons and the rudder.

#4 feda Apr 01, 2009 05:16 PM

Thank you, Scott, for sharing the pictures and your thoughts with us.

I agree with you on your analysis of the fuselage structure. Obviously, the flat bottom is there more for strength than for appearance. The box-like structure should improve the rigidity of the fuselage.

I like to use 3M Scotch 6225N for hinges. It's flexible, tenacious, and safe to use on foamies.

#5 Boss248 Apr 02, 2009 09:29 PM

It looks really sharb..I lilke it but are you going to power it with??


#6 groovejet Apr 03, 2009 05:00 AM


If I can get it to balance OK I will use a Scorpion 2215-18 motor on a GWS 10x6 prop. I'll use a Turnigy Plush 18A ESC because I still have a few and Rhino 3S1050 20C batteries. This combo will draw about 18-19 amps static and produce about 1000g of thrust. That should be enough :D

#7 Boss248 Apr 03, 2009 09:54 AM


Originally Posted by groovejet

If I can get it to balance OK I will use a Scorpion 2215-18 motor on a GWS 10x6 prop. I'll use a Turnigy Plush 18A ESC because I still have a few and Rhino 3S1050 20C batteries. This combo will draw about 18-19 amps static and produce about 1000g of thrust. That should be enough :D

The one down side to the scorpions is the weight and I had one burn up and an esc but they replaced both motor and esc..with no problem at all.Very good customer service.


#8 groovejet Apr 03, 2009 03:29 PM


Originally Posted by Boss248
The one down side to the scorpions is the weight and I had one burn up and an esc but they replaced both motor and esc..with no problem at all.Very good customer service.


The 2215-18 that I have standardised on for these sorts of planes is only 3 or 4 grams heavier than a Hyperion 2213-20 ready for use (with x mount and screws). The Scorpion can handle more input power and generates more thrust if it is wanted, though the setup I use here is a balance betwen power and efficiency, more weighted towards power. The Hyperion could just squeeze out similar numbers if I didn't use full throttle too much, but that would be pushing the motor very hard. The Scorpion is cheaper and has extra headroom.

Scorpion customer service is definately good. Which Scorpions have you tried?

#9 groovejet Apr 04, 2009 05:09 AM

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Well the plane is ready for its maiden. Despite finishing it late afternoon, I didn't maiden it today because I was having an afternoon snooze ;) .

I really like the shape of the main wing. It reminds me of a Katana wing and looks very elegant to me. Here are a few photos of the completed plane. Sorry if some photos look similar to each other or previous photos.

I made a few mods to the plane while I was building it. This is based on my experiences with a variety of similar planes from various manufacturers.

I made the following mods:

- I added some 10mm thick EPP behind the motor mount as I felt that the standard setup was a bit weak. I know that eventually I'll go in hard on the nose, so I'd rather add a bit of foam now to hopefully avoid a complicated nose rebuild later.

- I moved one of the internal fuselage triangular bracing piecs back about 30mm to give me the ability to get the battery further back if required.

- I sealed the aileron and elevator hinge gaps with Blenderm tape (not shown in photos).

- I added a piece of carbon fibre to brace the landing gear. I tied it on with cotton thread and then CAed and "kicked" it.

- I coated the foam area around each servo wood frame with a coating of 3M Scotch 6225N glue to strengthen the foam. This is because the foam can flex a little as the servo pushes the control surface to full deflection. I've seen this most commonly on the elevator servo on a few Hokusei planes. I haven't noticed any flight problems because of this but I'd prefer to stiffen up the area to prevent it. A layer of Scotch 6225N or hot glue or some fibre tape should solve this issue.

- To further reduce the stress of the elevator servo deflecting a long way, I added a small piece of 10mm EPP inside the fuselage that fills the "gap" between the elevator servo and the other side of the fuselage. This will relieve the stress on the servo frame an surrounding area as the servo pushes hard.

- The foam around the aileron servos seems quite flexible so I coated this area with Scotch 6225N glue as well and now it's noticeably stiffer in the servo area so there should be less chance of tearing out the servo frame over time.

- I attached the tail skid using fibre tape. The stock method would be stronger but my method was easier. I don't tend to stress this area much so I think it'll be OK.

The AUW is 455Xg with a Rhino 3S1050 20C lipo. I wasn't aiming for a light build as I'll be throwing this plane around very hard. You could build one 30g lighter or more without much trouble if light weight is your main objective.

#10 groovejet Apr 06, 2009 08:52 PM

Flight Impressions
I maidened the Ultima BX a few days ago but there was some wind so I had to wait until today to get it trimmed out properly. Now that it's trimmed I can say for certain that it's a really beautiful flying model. It has nice pattern flying charactersitcs but with a twist; on max throws it is very, very responsive and can pull off some very good moves. This is the flying style that I like best; precision for pattern and great responsiveness for aggressive 3D. I'm very pleased that I bought this plane as right now it's in my top 3 for enjoyable flying.

Some particular highlights of this model:

- Very stable with great tracking and responsiveness at low speed; it really floats around

- Very easy to hover

- Fantastic knife edge; can go really slow and at high angles of attack. I spent a lot of time doing this today as it's very enjoyable with this plane

- Excellent rolling harriers

- Very tight loops can be done with it basically rotating around the main wing.

- It looks great. I find the Katana'ish shaped wing very appealing

I have it balanced and trimmed very well and it is flying very precisely. I found myself spending more time flying slowly than I usually do because this plane is enjoyable to just cruise around. I remember feeling the same about my Primus Z when I first flew it. When I cranked up the speed and flung it around it performed well. I'm really happy with this plane!

#11 maiden-crash Apr 06, 2009 11:49 PM

Great stuff Scott. Ill have to visit next week or so just to see how good it is hehe.

#12 groovejet Apr 10, 2009 06:49 AM


You better come over quick before I destroy it flying it too low at high speed :D

I had a knife edge mishap that basically tore the foam behind the wood motor mount almost completely through, leaving the motor just hanging on. The nose area tore up pretty badly too, but I haven't (yet) had an EPP plane that I couldn't repair. I've reapired it and it looks pretty good considering the extent of the damage. I flew a few packs in it today to confirm that all is well. My thrust angle is slightly off but it's flying very well once more. It's a really great pattern plane but with its high level of responsiveness it can do aggressive 3D moves too.

I have a friend lines up for Sunday morning to film some of my flying. He's never filmed me before and the last time he saw my fly was about a year ago so he's in for a rude shock when he sees how rapidly these planes change direction :D . If I get any decent footage of this plane I'll post some.

#13 rmgmag Apr 10, 2009 10:10 AM

How does it compare to the Primus? Could I use the same components from the Primus and move them over to the Ultima?

#14 groovejet Apr 10, 2009 07:15 PM


Originally Posted by rmgmag
How does it compare to the Primus? Could I use the same components from the Primus and move them over to the Ultima?

Hi Bob,

I haven't done a direct comparison of the Primus and the Ultima and I haven't flown my Primus outdoors in a while. My Primus is now dedicated to indoor flying as it has the right combination of characteristics to allow me to enjoy flying it in a small area.

The Ultima BX has the same confidence-inspiring, goes where you aim sort of feel so I'd say they're roughly similar but the Ultima BX is possibly stiffer in the fuselage with less tail twist if you fly it aggressively because it has a box shaped fuselage.

My Ultima ended up 455g with the use of lots of glue, a 62g motor, 98g battery and a few simple mods to add a few grams. My Primus weighs close to this, so a Primus setup should work fine. I felt that the nose area of the Ultima BX is a little light so I beefed it up with some extra foam behid the motor mount (I did the same on the CST Katana) and added a fair amount of glue to hold it all together.

The Ultima BX is a very nice kit at current prices on Max's www.bestvaluerc.com site. I had my kits shipped out of Hong Kong and this reduced the postage cost considerably.

#15 groovejet Apr 12, 2009 09:22 PM

I got out of the slow flying mood I was initially in with the Ultima BX and now I really thrash it like most of my planes ;) . The Ultima BX is a really fun plane and is definately one of my favourites to fly.

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