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Detailed Assembly Instructions for the Gizmo Precision Freewheeler

Free flight rubber-powered model airplane builders are craftsmen of the highest degree. The Precision Freewheeler will help you get the best performance possible from your models - it offers the many features described on the PFW Product Page and each of these features will save you time and effort as it improves your ability to put in award-winning flights. If you have specific questions, see the FAQ section.

1. Introduction:

You have purchased a precision machine. Please take a few moments to read this manual. We've made every effort in the engineering and manufacture of the Gizmo to make it as user friendly and reliable as possible. In order for you to enjoy all of the features and benefits the device has to offer, a good understanding of how it works and how to make it work is needed.

2. What's In the Box


3. How Does The Free Flight Gizmo Precision Freewheeler Work?

The Gizmo employs an Automatic Transmission Mechanism which senses when the motor's effective power has been used and shifts the motor into "park" while at the same time shifting the prop into "freewheel". This action ensures that some tension always remains in the motor to keep it taut between the Front End and the rear peg.

Shown in Figure 1 a wound rubber motor (which is held in the Sleeved Clevis by the Hollow Clevis Pin) compresses the Tension-Sensing Spring located in the Prop Drive Spinner (or old version Drive Dog, available in the Gizmo Rebuild and Customize Pack PFW-02). When the Prop Shaft Drive is screwed aft and out of the Nose Button Cluster, the motor is able to turn the prop which is now in the slots of the Spinner.

  Wound Motor Shown With Prop Drive Dog Option

(Note that the plastic drive dog has been replaced with new FAC dog - click here)
Shown in Figure 2 when the motor is mostly unwound and there are only 55 to 60 grams of tension remaining, the Spring expands, moving the Prop Shaft Drive forward until it engages the Nose Button and screws itself forward, stopping the motor from turning and moving the Spinner/Dog and Spring forward and out of contact with the prop. The Prop Shaft MUST be free to both rotate and move fore and aft in the Nose Button and the prop.   Parked Motor Shown with Prop Drive Spinner Option

Bent shafts, wicking Cyanoacrylate (Super) glue and grit cannot be tolerated.
Lubrication of any kind is not required, and may cause dust and dirt build-up in mechanism.
Do not braid the rubber motor as some slack in needed in the motor for the freewheeler to work.

4. Optimizing Prop Performance

The prop is a high-performance prop with 1.25 to 1 P/D; however, it may be out of balance. A strip of lead foil tape is included in the parts pack of PFW-95s only to remedy this condition. Apply lead tape across the rear side of the light tip. With a sharp knife, cut and remove narrow strips of tape until the prop is in balance.

5. Installing the Gizmo Into Your Model (Click on photos for larger view series)

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Enlarge the nose block hole to 3/8" (9.5mm) diameter. If nose button is made of very hard wood, cut in small notches for thrust-adjusting-screw tunnels. If wood is softer, cutting notches may be unnecessary — just push nose button in firmly.
To view a diagram of a typical installation, click here.
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The Gizmo is designed to fit nose blocks that are up to 5/16" (8mm) thick. If your nose block is thicker, carve a conical well at the back about 5/8" (16mm) dia. to accommodate the thrust adjustments.
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To maintain the thrust line adjustments, apply a coat of white glue, or cement like Duco or Ambroid, as shown. DO NOT USE THIN CYANOACRYLATE HERE AS IT WILL WICK INTO THE UNIT AND MAKE IT USELESS!
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With the Sleeved Clevis removed, press the Nose Button Cluster into the nose block (see above for notes re cutting notches). If you install the Gizmo with two screws of the triangle across the top of the nose block and one at the bottom, then adjusting only one top screw will give both down and side thrust simultaneously. If nose block hole is 3/8" as specified, Nose Button Cluster will penetrate the nose block to correct depth.

6. Loading A Rubber Motor into the Sleeved Clevis (Click on photos for larger view series)

The Sleeved Clevis is designed to hold from two to eight strands of 1/8" (3.2mm) wide rubber strip. Remember — it is important that there be some slack in the rubber motor system for the freewheeler to work; i.e. do not braid the motor.
(Once practiced, loading the motor becomes easy).

Start Loading Rubber
Pull Motor In - Careful Not To Pinch the Motor
Secure Pin
Figure 3 Start Loading Rubber
Figure 4 Pull Motor In
Figure 5 Secure Pin

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If the Hollow Clevis Pin is in the Sleeved Clevis, then slide the Hex Key/Anchor Pin through the head end of the Hollow Clevis Pin and pull the Pin forward until its head clears the molded retainer tab. Loop the motor strands over the extended Hex Key/Anchor Pin and slide them down the Hex Key/Anchor Pin until they go into the mouth of the Clevis. (Figure 3)
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Carefully slide the Hex Key/Anchor Pin down and rotate it to pull the motor into the Clevis, making sure that the Hex Key/Anchor Pin end doesn't nick the rubber. (Figure 4) Then extend the Hex Key/Anchor Pin through the opposite hole in the Sleeved Clevis.
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Slide the Hollow Clevis Pin into place.
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Ensure that the head of the Hollow Clevis Pin is under the molded retainer tab. (Figure 5).
Please note that it is important to use a clevis pin with a head and to always insert it so the clevis pin head slips under the molded retainer tab otherwise the pin will work itself out and release the motor during the flight.

7. Winding the Motor

Connect the Sleeved Clevis to the Winder Attachment accessory (tie this vital accessory to your winder hook with a lanyard so it won't get lost) by plugging it in and twisting the assembly clockwise until it stops rotating. Connect the Winder Attachment either directly to your winder or to your winder through a "blast tube" set-up, and stretch wind the motor in the normal fashion.

8. Connecting the Wound Motor to the Front End

Slide the Hex Key/Anchor Pin accessory through the Hollow Clevis Pin (in this case, it is best to insert the Hex Key/Anchor Pin into the head end of the Clevis Pin). Using the Anchor Pin as a handle, slip two fingers between the Anchor Pin and the front of your model, straddling the motor. Close your fingers to trap the Sleeved Clevis. Remove the Winder Attachment by twisting it counter clockwise until it stops, and then unplug.

With the Freewheeler in the glide mode (Prop Shaft screwed forward), hold the Front End by the Spinner/Dog and plug the Freewheeler's Prop Shaft Driver into the Clevis and twist clockwise until it stops, locking the unit in place.

Pull the prop into the spinner/dog, hold firmly, carefully remove the Hex Key/Anchor Pin and plug the nose block into your model.

Note that the Freewheeler is "locked up" in the glide mode so you don't have to hold the prop while waiting for that all-important thermal!

9. Getting Ready to Fly

To put the Gizmo into "Power Mode", use two fingers to pull the prop forward into the Spinner/Dog and hold it there while you turn the prop two turns clockwise (as viewed from front). Give the prop another three turns clockwise to ensure that the Gizmo is in the correct mode and you're ready to fly.

10. Adjusting the Thrust Line

The Thrust Adjusting Screws are located in a triangular pattern and are accessible from the front with the nose block in place. If you install the Gizmo with two screws of the triangle across the top of the nose block and one at the bottom, then adjusting only one top screw will give both down and side thrust simultaneously. One complete turn of any screw will shift the thrust line approximately 2.5 deg. up to a maximum of 10 deg. Use the Screwdriver/Anchor Pin accessory to turn the screws as it is the correct size for the task. Also, make sure, when making large thrust adjustments, that all the screws are turned out far enough so that no jamming at the Nose Button perimeter occurs.

11. Things to Remember

a) The Gizmo doesn't require lubrication but must be kept clean and free of grit.
b) The Gizmo will not work with a bent prop shaft.
c) The freewheeling mode will not work if there is tension in the system, i.e. do not braid motor.

d) Be very careful when using thin CA glue close to the Gizmo it might wick into sensitive parts making them useless.
e) Ensure that there is clearance at the rear of the nose block for the Clevis assembly when the thrust line is offset.
f) Make sure that the head of the Hollow Clevis Pin is under the molded retainer on the Clevis.
g) Don't lose vital accessories like the Winder Attachment and Screwdriver/Anchor Pin.

Made in Canada