Hey guys,

I’m half way through assembling a World models Intruder and I’m looking at this thing with a YS110 resting on the engine mounts ready to start drilling some holes and think to myself there is NO WAY a 15/8 prop is going to clear the ground. Has anyone else had problems like this. The box calls for a 60 2 stroke or 90 4 stroke.

Looking at this plane you would be flat out fitting any prop over 13 inches which seem to be very odd for a plane with a 63 inch wing span

Anyone else had a similar problem with an Intruder and ground clearance?

.

Dogz,

You're right, there's very little clearance for a 12" prop let alone anything larger. I initially fitted a .60 2C and the ground clearance with a 12" prop certainly cleared the deck but the low main wheel height meant that the tail would touch the ground when landing. I also used larger wheels as my field has a bumpy grass track for a strip.

This plane is not well set up for an inverted motor as the tank is way too high - go side mounted or upright or reposition the tank. I tried a perry pump which helped things a lot but only to determine that the .60 just isn't enough grunt so now it has .90 FS. I haven't flown it yet so no idea of the performance. To solve the fuel tank position issue, persisting with an inverted motor as the cowl is all cut for it, I fitted a Sullivan 10oz tank in line with the carby of the .90FS. This meant drilling a new hole for the tank outlet (about 2" lower than the original tank outlet hole and positioned slightly to one side to clear the steering pushrod (wire). Also, it meant making up a supporting platform and brace to keep the tank secure. The new tank is only 1oz smaller than the original so I'm hopeful that the FS will be more economical than the 2C and I'll still get 10mins out it.

Back the ground clearance issue. To use larger than a 13" prop you will need to:
- bend up new main gear,
- make a new support guide for the nose wheel so that you can lower it (ie feed it through the bottom hole of the engine mount then into a home made support (drilled GRP or hardwood). Then lock the little collets (round things with a grub screw) on nose gear on both sides of the lower engine mount. reposition the steering horn and file a flat side on the nose gear to help lock the steering horn.
- use larger wheels - those little ones are only good for concrete or bowling green quality strips.

The heavier motor meant a nose heavy plane so I made a battery compartment aft of the wing retaining bolts ie between the bottom of fus and where the push rods are. Cut a 1/8" slot in one side of fus about 5" long. Slide in 1/8" sheet (cross grain) and glue. Put triangular syupport on other side of fus to give the new platform strength. Place a wall at the back of the platform to prevent the battery sliding backwards. Pack the compartment with foam and squeeze in the battery. Run a 12" battery extension lead under the servo tray to the switch mounted in front of the servos - be sure to guide the lead away from the push rods. It all fits well and balances perfectly.

Apart from all that the plane was an accurate flyer with no bad tendencies - I just hope to have enough power to really enjoy it. Your YS110 will provide ample power. I'm about to use a 13x7 and try a 13x8 and a 12.5x9. Without changing that main gear no larger props are viable. I'll let you know how it goes in a week or two.

Arthur

Arthur,

Great to get some feed back. I'm going down the similar path as you said, it’s great to get a second point of view. I moved a fuel tank (380cc) to the CG point of the wing and am using the small compartment in the nose for a 6oz tank giving me 500ml plus of fuel. With the YS the centerline of the tank is not an issue I hope. I did fiberglass the inside of the fuselage because I had to remove a gusset to fit the tank.

The nose wheel….. I was going to change the main wheels to 3" duBro wheels and bend new landing gear and say a 2.75" front. I was going to do exactly what you said in regard to the support for the front wheel. I have an old tricycle brace from a Seagull Scanner that I think will fit between the 2 arms and was going to lower the arm by 20 to 25mm

I had concerns about the nose weight and balancing, I moved the rudder servo to the elevator servo hole and am running twin JR E381’s on the back. I think they have 3.1kg rating each. 2 of these are the same weight as a JR591. I was hoping with these on the tail it would help balance out the engine. I haven’t let my self a lot of options for the placement of the battery. Only just in front of the servo tray or in the nose compartment. If I need more tail weight I’m going to be stuck

I was planning to run a 14/9 3 blade prop on the YS but it’s going to be very tight in the ground clearance side of things. I should take some Pics.