My latest seaplane, well, float plane.
I wanted a glow powered float plane and thought the Hobbico Nexstar had a nice look to it and could be easily configured with flaps.
I installed a OS 52 FS with a 12x5 APC and test flew the plane for 5 flights before I turned it over to Art Aube in Skowhegan, Maine for a set of his floats.
I fly the plane with seven channels on a DX7 with a 5 cell 2000 mah high capacity flight battery. The water rudder has its own servo in the left float (a HS-81MG) and is mixed with the rudder controlled by a switch. AUW without fuel is 8lbs12ozs.

Takeoffs and quick and easy as it is on step very quickly and the plane will cruise in level flight at half throttle. Landings are easy also. In the air, however, it is a different story. It is not as stable as hoped. Ailerons not effective at low speeds and you need to fly with the rudder. Of course, the ailerons are smaller due to flaps which greatly aid in takeoffs. Ailerons are fine at faster speeds. There is quite a lot of dihedral in the wing. It just seems to react suddenly to roll changes in the air at speed.

I did have it flown by a real expert and we did some setup changes to throws and more will come. It has been suggested I add a subfin to increase vertical area. Thoughts??

Joe

Adding a sub-fin (ventral fin) will definately help. Add about 50% of the area of the existing fin and rudder. Also check and make sure there is no binding in your ailerons controls.

With that much dihedral, you have a lot of level flight stabiltity that your ailerons have to overcome to make it bank. It's a bit of work, but taking all of the dihedral out of the wing will make it handle MUCH better in the turns.

Jim

Thanks, Jim.
I will work in that direction and add a fin. I do have a friend with a Nexstar and he took most of the dihedral out by bending the wing joiner rod (steel). The wing half's are only held together by the center plastic section so it wouldn't be a very hard job. He flys only from land. I will also make sure that the ailerons don't have any issues. When I flew from land for 5 flights, all was fine and it flew well but not as good as my trusty LT-40.

Again, thanks for your help.

Joe

Hi Jim
I have made changes to dihedral - cut it in half. I measured an angle of 170 deg at the wing root and bent the steel joiner rod so I now have an angle of 175%. Also added a vertral fin and it is just about equal to the vert fin and rudder area. Looks big!! Hope I can fly it this weekend to see the results.

This photo shows difference in dihedral and fin.
Joe

I'm sure you will like it a lot better this time.

Forgive me for stating the obvious, but you did remember to rebalance the airplane after adding the subfin, right?

Jim

Jim,
I hate to say this but.......
I will remount the wing tomorrow and check!

Going to attach a note to the plane right now!
Thanks!!!!!!!!
Joe

Thats a great looking Nexstar! I'm hoping to make some of the changes you made to my Nexstar on floats. How did you attatch the subfin? Did you use the nylon bolts to hold the tail on when you built her,and if so how did you work around it? Can't wait to see how your next flight goes, thanks for the info-Harold

Speaking of the lack of aileron's. Instead of cutting the aileron's in half and adding an extra servo, on mine I just left the dual aileron servo's on there with the wing unmodified and programmed in my flapperons on my xmiter. I don't have any of the troubles that you do. I have full control rather it is in a knife edge, or 5 inches above the runway inverted. Mine handels GREAT! It would be a good and LIGHTER solution to the problem you are having I think. Of course my two sense worth isn't any good to you now unless you are willing to buy another wing.

However I was interested in being able to put floats on my nexstar. Which ones did you use? Are they easily swapped out for wheels? I would only be flying floats for a couple of times a year.

quote:

ORIGIANL: jpg0529



My latest seaplane, well, float plane.
I wanted a glow powered float plane and thought the Hobbico Nexstar had a nice look to it and could be easily configured with flaps.
I installed a OS 52 FS with a 12x5 APC and test flew the plane for 5 flights before I turned it over to Art Aube in Skowhegan, Maine for a set of his floats.
I fly the plane with seven channels on a DX7 with a 5 cell 2000 mah high capacity flight battery. The water rudder has its own servo in the left float (a HS-81MG) and is mixed with the rudder controlled by a switch. AUW without fuel is 8lbs12ozs.

Takeoffs and quick and easy as it is on step very quickly and the plane will cruise in level flight at half throttle. Landings are easy also. In the air, however, it is a different story. It is not as stable as hoped. Ailerons not effective at low speeds and you need to fly with the rudder. Of course, the ailerons are smaller due to flaps which greatly aid in takeoffs. Ailerons are fine at faster speeds. There is quite a lot of dihedral in the wing. It just seems to react suddenly to roll changes in the air at speed.

I did have it flown by a real expert and we did some setup changes to throws and more will come. It has been suggested I add a subfin to increase vertical area. Thoughts??

Joe



sorry, my response is to this post.



Mike

Hi Guys...
Well, I am very happy to report that the Nexstar flys like it should now!! Ailerons will now bank the plane at slow speeds and there are no "sudden" banking events as before. I still use the rudder when I fly but as I stated, you can now fly the plane with ailerons.

As for the subfin, it is attached at the rear with the rearmost plastic bolt that holds the tail feathers in place and at the front with a plastic screw just going into a tapped "CAed" hole in the fuse. I put a notch in the fin where the front plastic bolt is. Seems to hold just fine but I only have two flights on it with the mods. I built it with 3" wide 3/16 sheet balsa and glued that to a piece of good spar 1/2 x 1/4 balsa. That piece of "spar" overlaps front and rear for the mounting screw/bolt.

I bent the "joiner rod" 5 degs and everything just slips together as before but now with only half the dihedral.

As for flapperons, I always use a separate channel for each aileron servo and could easily program them as flaps for takeoff but I really like to play!! That's one reason I decide to buy that particular plane. I use that feature on my Bonnie 20 and it benefits on takeoff but can introduce a tip stall on landing if you forget them!! And as I may have mentioned, this plane flew just great until the floats were added. They are what caused the issues I had.

I had the floats installed by a friend that runs a small hobby shop here in Maine - Art's Hobbies - Skowhegan, Me. He builds his from foam, adds a hardwood mounting strip and fiberglasses them. A bunch of us up here use them and they work very well and stand up to abuse. These are 38" and he mounts them with music wire. He added hardpoints inside the fuse, drilled holes into them from the side, and the MW just slides into those holes and are held in place by a brass bracket with tie wraps. Unfortunately, the plane is at camp and I won't have access to it for photos until I return from there in several weeks. The attached photo is not that great but does show up the mounting area and the fin

BTW, the 52 OS FS is more than enough power for this plane as I fly it. Will loop from level flight. Cruise at half throttle. And I wanted it for casual flying. If I want aerobatics, I will fly my Seamaster. It excels at aerobatics.

Hope this answers any questions.
Joe

Hi Joe: thanks for all the info. I made the same changes -here are some pics-was easy to do with your help. Harold

Harold, Looks great!
And it is obvious it can handle some wind and water!

Just curious.....What is your AUW?

Joe

Hello Joe: My AUW is approx. 9 lb, I used a spring scale before I took it to the lake-not sure how accurate it is. I'm still having problems getting this plane to ROW. Float to wing incedence is 2 deg, step is 1/2 to 3/4 inch behind Cof G. The day the pics were taken it was quite windy and rough. I knew I shouldn't fly but I thought it might be the last chance. So that day it lifted with no problem, but as I made the downwind turn the wind blew her down and she skipped off the water once and then caught a big wave into the float tips. You can guess what happened-tore the mounts out of the fuse which took about 2 hrs to repair. Tried again yesterday and couln't get her to ROW. The lake was a litlle less rough than in the pics but the wind was far less. Next week may be my last chance-I'm thinking I should have stuck with flying boats, might be my new winter project( looking at the LG Neptune-anyone have experience with this craft?) I'm running an OS46fx with an 11x5 prop. I wonder if I'm underpowered?

Please excuse a silly question, but in some of your photos it looks like the wing incidence is negative to the top of the floats. You do know that the wing should be 2 degrees positive to the floats, right? (In other words, the floats should be nose down vs. the wing.)

Jim

definitely positive! 2 degrees Robart incidence meter

I believe you have enough power though most will insist on larger engines. Mine with a OS 52 FS has more than enough power for takeoff even without flaps in a very light wind. Did multiple takeoffs yesterday without issue. Had five 15 min flights and it flew great.

As Jim mentions, incidence is very important. I was working on an electric float plane earlier this year and tried changing the incidence to parallel with the floats and it wouldn't lift off at all. You can always insert a shim under the front float mounts and give it a try. Carry a couple sets of shims with you for testing. If you set it up as he suggest, I'll bet it will fly without trouble. Does your mount in the front allow you to slide it up/down in the nose wheel brackets? If so, easy answer to change incidence.

Give it a try as Jim suggests and let us know.

As for Seaplanes, I haven't seen a Neptune but it looks like a knockoff of a Seamaster and the Seamaster is a great seaplane - highly recommended. If you want a Seaplane, get a Seamaster and you won't regret it. IMHO!!!
Joe

Here is a photo to give you some inspiration!

It is very easy to change incidence as the front mount is held in to the original mount with collets. I have set the incidence to 2 deg pos. with the wing cord to the top of the floats. Thats what everyone seems to set it to. Maybe I should increase it to 3 deg and see what happens. Sigh- only I brought the canoe home last night. Thanks again for all the input Harold

Harold:

In this picture is looks like the wing is quite negative to the the trim line on the side of the fuselage and to the top of the floats. Is this an optical illusion?

Jim

It must be an optical illusion Jim as I have double checked this several times. I still have the wing anti-spin droops on-perhaps this adds to the illusion. Say Joe-is your incidence set with the wing cord or did they maybe use the flat underside of the wing, any chance you can check and let me know? I used a robart incidence meter on the wing and an angle guage on the float to adjust mine to 2 deg pos. And you are right Jim- it sure looks negative in the picture,but the meters shouldn't lie. I also tried installing the training flaps after cutting 1/3 off-this helps get on step when going with the wind, but don't know if they will help otherwise. I have a futaba 6xa which I should use on this plane and then I could use flaperons,but I just haven't had time to check and figure this radio out yet. I still believe it will fly once I get everything right. I sure am thankful for R/C universe and all you fellow fliers and the trove of info you have supplied me with-thanks, Harold

Harold,
I just went out and measured the incidence on my Nexstar. 2.5 degs Positive using a Great Planes Accupoint Laser Meter. The guy that set mine up uses his own method - he doesn't own a incidence meter - but he has been doing it for years and his setups work. I first zeroed the meter on the top of the floats and then mounted it on the wing at the root to get the reading and then back to the top of the floats to verify I hadn't disturbed the zero setting. The step is at the CG as best as I can determine.

I have the droops on at the moment and flew with them this weekend but can't really say what difference they make.

Although I have looped and rolled the plane, most of the time is touch 'n gos. We try to drag the water rudders without the floats touching!! Fun and challenging!

HTH,
Joe

Joe- how did you mount the meter to the wing? Does it read the flat bottom of the wing or does it measure the wing cord? Harold

Hi Harold, since a photo is worth more than many of my words, here it is.
Just slips over the wing and you tighten the brackets to align to wing cord.

Joe

Thanks Joe- same as the robart,so I guess were only 1/2 deg. different. I'll try mine at 2 1/2 deg and see what happens, if I get another chance, Harold

O.K.-so I changed the incidence to 2 1/2 degrees and I moved the floats ahead 3/8". So the step is now 3/8" behind Cof G. In the water she seemed a little faster on the step and you could tell she wanted to lift, so I then tried 3deg of incidence -seemed to veer to the right but still not wanting to lift off. A fellow flier came down and thought my floats were too heavy and I was getting water in one of the floats so under his advisement I gave up. So far I have added about 6oz in total to the front of the floats so the AUW must be close to 9 1/2 lbs by now. Had to bring the plane home- at least its in one piece- I might put the wheels back on as I am starting to get frustrated. I ordered a CofG tool so I will double check everything again-thanks everyone for all your input -If I ever get this plane up I will let you know-Harold

Hi, all
I dont have my nextar set up with floats, but i did lower the dihedral.
One word of caution!
I did it by bending the metal bar and reinstalling it, I attached the wings using the plastic center.
On the second flight the bar twisted and the bend ended up instead of down, you wouldnt beleive the dihedral i had then!
I got her to the ground ok and later i installed the bar permenantly with epoxy, and still used the plastic center, only now the
wings cant be taken apart. But in a way thats not really a bad thing.
Anyway, just wanted to tell all that used this method to change the dihedral, that the bar can and probably will slip to
the opposite direction.
I was kinda lucky the wings didnt rip off when that happened. Good luck all! Scott