Frequently Asked Questions



What is included with Performance STOL flaps?

Both certified and experimental flaps include everything needed to mount the flap system onto your Cub or Cub-type aircraft.

How much does the certified Performance STOL system weigh?

The certified double-slotted flap system for the stock Cub wing has a replacement weight of roughly 12 lbs over the OEM single-flap system.

Do I need a special stabilizer to fly with these flaps?

No, you do not need a modified stabilizer. Performance STOL began initial design work for a custom stabilizer early in the development of the Keller flaps, but the project was scrapped. Certified flaps were extensively tested and ultimately approved on Cubs with standard tailfeathers.



What does installation entail?

Depending on the setup, it takes the average mechanic or homebuilder 8 to 12 hours to install the first time. Installation includes limited riveting and drilling. In most cases, installation requires only minimal fabric work (cutting, not repair).

Are there any changes to the fuselage, flap handle, internal wing, cables, or bell cranks?




Does the new Double Slotted Flap system require more force to deploy than the stock Piper flap?

We have not noticed any change in the deployment force.

How does the double-slotted flap system compare to slats, slots, cuffs, or VGs?

Most leading edge devices work by delaying the stall to a higher angle of attack. You can fly slower but only by increasing the angle of attack, which reduces over-the-nose visibility. 

Trailing edge devices, on the other hand, allow you to fly slower at a lower angle of attack. This makes flap modifications much more desirable for pilots who want STOL flying, not just slow flying.

How much reduction in stall speed can I expect to see?

Most Cub pilots see a 4- to 5-MPH reduction in their stall speed compared to the stock configuration. More relevantly, they see a reduction in their landing and takeoff speeds.

What is the greatest benefit of the Double Slotted Flap system on a Cub?

Slower landing and takeoff speeds at a flatter deck angle. This gives you increased visibility and shortens takeoff distance since you do not need to be at a high angle of attack to rotate.



How do I get on the certified flap waiting list?

Place an order and put down a deposit. You'll find instructions on the Order Form page.

How are Performance STOL flaps shipped?

Flaps are crated and shipped freight. We'll provide a freight quote based on the shipping address.

Why do I need to provide dimensions for experimental flap configurations?

Every experimental order is a custom order. We need these dimensions in order to build the flaps for your specific application. It is very important that these dimensions are accurate! We will build the flap to these dimensions exactly. If the dimensions are wrong, the flaps will not fit your aircraft.

Why is full payment in advance required for the experimental configuration?

All experimental Performance STOL flap systems require payment in full prior to start of construction because the spars and skins are specific to your airplane. We therefore will not be able to use them for other customers should you change your mind.

What is the average delivery time for the experimental double-slotted flap system?

Experimental flaps typically ship 4-6 weeks from time of order and receipt of payment.