RV-15 at OSH

[GaryK]

Rian Johnson said the gross will be 2400# and the empty "will depend on how you build it."

I spoke with Brian about several things. As Louise said the GW is planned for 2400lbs. He wouldn't commit on the empty weight because they don't know yet. They are committed to having the ability for customers to install floats but it gets tricky. The more structure you add the heavier the fuselage gets. I believe they are trying to hit a compromise with some of the structure needed for floats part of the standard design but a float package that would add additional parts, and weight. I tried to get a ball park empty weight and threw out 1400 to 1500lbs. He came back quickly with it will definitely be below 1500lbs. I didn't ask about the nose wheel option but I'm sure they are also deep into how that will work without a major redo to the fuselage design.

I aslo mentioned the kit and plans OA were very well done. My 2 suggestions have been mentioned on this site many times. Pre bend the flap trailing edge to the final shape and either don't dimple the leading edge of the horizontal stab or dimple and break the edge in the factory. He said the flap bend is already taken care of on new kits and understands the challenge on the horizontal stab. No commitment on that one but leaning towards doing both in house.

 

[Phyrcooler]

I just watched a video wherein I saw more of the RV15 update slides. One noted that both occupants and panel are moved 5 inches forward. I remember this being mentioned previously. I was under the impression at that time that the “A-pillar” was being changed as a part of this - with the windscreen being more angled. Maybe I was just reading someone else’s opinion at that time - I don’t remember. Does anyone know what this configuration change includes?

Also, in reading the slide about spin testing, I’m curious how they can conduct spin testing without the final form of the fuselage? Isn’t there a chance that windscreen shape and angle can change the aerodynamic? This is outside my level of expertise. Or, maybe the actual exterior form of the fuselage is not changing? Curious if anyone picked up more insight while there?

 

[rvbuilder2002]

In a fully developed spin, the airflow over the tail is imposed at a fairly prominent angle from below and to one side
(depending on the direction of rotation) because of the strong yawing motion coupled with the relative AOA, so the only portion of the fuselage likely to have a direct impact on the spin characteristics is the aft tail cone which I think is pretty frozen external shape wise at this point. So a change in wind screen shape / rake is not likely to have any negative impact on spin characteristics.
.
Any change in cross section area fwd of the yaw axis could have an impact.
Think in terms of any surface area fwd of the c.g., that could have a lateral air load imparted on it as being destabilizing. If that area is increased, it is possible for the change to induce the same influence as if the vertical stabilizer / rudder area were reduced.
In this case I doubt the amount of change being described would have much influence, but I am certain that some follow up testing will be done, to prove that to be true or not.

 

[Ironflight]

In a fully developed spin, the airflow over the tail is imposed at a fairly prominent angle from below and to one side
(depending on the direction of rotation) because of the strong yawing motion coupled with the relative AOA, so the only portion of the fuselage likely to have a direct impact on the spin characteristics is the aft tail cone which I think is pretty frozen external shape wise at this point. So a change in wind screen shape / rake is not likely to have any negative impact on spin characteristics.
.
Any change in cross section area fwd of the yaw axis could have an impact.
Think in terms of any surface area fwd of the c.g., that could have a lateral air load imparted on it as being destabilizing. If that area is increased, it is possible for the change to induce the same influence as if the vertical stabilizer / rudder area were reduced.
In this case I doubt the amount of change being described would have much influence, but I am certain that some follow up testing will be done, to prove that to be true or not.

All completely true! I’ll also add that for the spin testing, they had actually moved the engine forward significantly and lengthened the cowl (adding surface area forward) to simu.ate the final fuselage’s aerodynamics. They restored the airplane to the original configuration for Oshkosh.

 

[rvbuilder2002]

All completely true! I’ll also add that for the spin testing, they had actually moved the engine forward significantly and lengthened the cowl (adding surface area forward) to simu.ate the final fuselage’s aerodynamics. They restored the airplane to the original configuration for Oshkosh.

A detail I was aware of, which is why I mentioned the influence potential.

I should have included the fact that testing had already been done to quantify the effects of that type of change, but I wasn’t sure if that had been shared publicly yet.
Now that they fully know what to expect, I think it is highly likely that some low level spin testing will be done with the final fuselage configuration to confirm the characteristics match the original results.

 

[Phyrcooler]

All completely true! I’ll also add that for the spin testing, they had actually moved the engine forward significantly and lengthened the cowl (adding surface area forward) to simu.ate the final fuselage’s aerodynamics. They restored the airplane to the original configuration for Oshkosh.

Ahhh… interesting info, and makes sense. To both yourself and Scott, thank you for the responses.

I am assuming they made the move forward to simulate (or possibly test installed??) a lighter engine? The FAQ slide had a bullet point of “Parallel Valve Motors”, but I’ve not seen comments providing any updates on engine choices.

I’m curious if they’ll have more than one engine option available under E-LSA Certification?

 

[rocketman1988]

Ahhh… interesting info, and makes sense. To both yourself and Scott, thank you for the responses.

I am assuming they made the move forward to simulate (or possibly test installed??) a lighter engine? The FAQ slide had a bullet point of “Parallel Valve Motors”, but I’ve not seen comments providing any updates on engine choices.

I’m curious if they’ll have more than one engine option available under E-LSA Certification?

I thought I saw in one of the slides that engines weighing in at 265 pounds or more would work...

• Stall speed is under 45 knots at gross weight, and better at lower weights.
• Takeoff and landing distance is less than 400 feet.
• Spin testing has been completed with flawless success.
• Designed for an engine of 175 to 220+ hp (engine at least 265 pounds).

 

[OffTheRivet]

My 2 suggestions have been mentioned on this site many times. Pre bend the flap trailing edge to the final shape and either don't dimple the leading edge of the horizontal stab or dimple and break the edge in the factory. He said the flap bend is already taken care of on new kits

Great news! That is one part of the wing kit I have been nervous about, relieved that the flap skin will come pre-bent!

 

[Louise Hose]

Just to confirm, they are going to rake the windscreen differently and they are now opening talking about also supporting an IO360 angle valve engine, which is what we have just bought for our RV-15.

 

[flymore]

I thought I saw in one of the slides that engines weighing in at 265 pounds or more would work...

• Stall speed is under 45 knots at gross weight, and better at lower weights.
• Takeoff and landing distance is less than 400 feet.
• Spin testing has been completed with flawless success.
• Designed for an engine of 175 to 220+ hp (engine at least 265 pounds).

I believe those limits would also green-light the UL520T.