J&H Saturno V3.6 User manual

J&H Aerospace
Saturno V3.6
P-30 Endurance model
By
www.jhaerospace.com
Alexandre Cruz’s contest winning P-30, optimized for laser cut precision assembly

Saturno V3.6
Building Instructions
Congratulations on your purchase of the Saturno! You are about to build a high performance rubber model
capable of competitive, long flights. This is a full kit containing all parts necessary for rigging a fuse dethermalizer
equipped competition model. Refer to the notes on the plans for basic construction notes. We recommend sealing
the entire structure with a coat of 50/50 thinned nitrate dope before attaching the tissue by soaking it with
acetone to soften the dope on the airframe. The completed flying surfaces should be given one or two coats of
nitrate dope thinned to 30%. Use an electric ignitor to light the dethermalizer fuse to avoid accidentally igniting the
tissue on the model with an open flame.
1. Parts list
Before beginning construction, please verify that your kit contains all of the necessary parts listed below and
shown in Figure 1 and 2. Please be aware that some of the laser cut parts may have separated from their carrier
sheet, so you should ensure that all of those parts are present and undamaged.
1. Full size plans
2. Parts Sheet #1: Longerons and spars, 1/8” balsa
3. Parts Sheet #2: Wing ribs, 1/16” balsa
4. Parts Sheet #3: Stab ribs, 1/16” balsa
5. Parts Sheet #4: Stab platform and dihedral braces,
1/32 ply
6. Parts Sheet #5: Fuselage jig and hard points, 1/8”
balsa
7. ¼” Al tubing, 1” long
8. 1/32” Piano wire, 15” long
9. Rubber bands for wing and tail hold downs (8x)
10. Spiderwire for DT line (36” long)
11. Tissue paper (2 sheets)
12. 1/4” nose bearing
13. 3/64” propeller shaft
14. 9.5” gray propeller
15. 1/8”x16’ rubber
16. DT fuse (10” long, 1”/minute burn rate)
17. Balancing clay
18. Kevlar thread (DT limit line, 36”)
19. 2-56 nylon screw
J&H Aerospace

Building the Saturno
You will need a large, flat surface to build your model successfully. We recommend a large piece of foam
or a suspended ceiling tile, as these surfaces readily receive pins required to hold the components down
during assembly.
Before beginning construction, be sure to acquire the materials and tools necessary to complete your
model. You will need glue suitable for bonding wood, such as cyanoacrylate (super glue, or CA), white
glue, wood glue, or Duco cement. Protect your work surface using a sheet of parchment paper or wax
paper. For cutting the wood parts apart, a SHARP single edge or double edge razorblade is needed. You
will also need glue stick or nitrate dope and scissors. A sanding block and CA accelerator (if using CA
glue) will be helpful. The glue stick or nitrate dope is used to attach the tissue to your flying surfaces.
Builders who suffer from allergies to nitrate dope may choose to use Eze Dope instead, however we
have found that nitrate remains the best option for long term durability.
Straight pins, or better yet, entomology pins, are very useful in holding parts down during the building
process.
Obtain a silicone-based lubricant for your rubber motor (DO NOT USE petroleum products such as WD-
40 or Vaseline/petroleum jelly as these will destroy the rubber in a matter of hours!).
For best flight performance, a heavy duty hand crank winder will allow you to wind more quickly and
stretch the motor for best winding results. We do not recommend electric winders as they provide poor
feedback, are fragile, and are generally much more difficult to manipulate than hand crank winders.

Lay parchment paper over you plans to avoid getting components stuck to the plans. Begin building by laying out
the fuselage sides as shown over the plans. For best results, build the second fuselage right over the first. This
method will require you to separate the sides later using a razor blade, but it provides virtually identical fuselage
sides.

Once you have completed the fuselage sides, assemble the fuselage jig as shown. This device will allow you to easily
jig the sides together into a straight fuselage.
Slide the fuselage sides into the jig and begin adding cross pieces to join them together as shown. If you stagger the
cross piece stations relative to the jig frames, you can avoid gluing the fuselage to the jig. The jig is not the full length
of the fuselage, so you will need to slide it down the fuselage as you progress with adding the cross pieces. Don’t
forget to add the sheeting at the nose. Once it is added, the fuselage will stiffen considerably.

Carefully remove the fuselage from the jig. You may have to slit some of the jig formers to slide the fuselage
completely out. Join the rear of the fuselage together and add the rear gussets (long thin triangles) and cross pieces
as needed. Some of the rear cross pieces may need to be cut down to length.
Assemble the wing pylon as shown. Do not attach it to the fuselage at this time.

Add the pylon rails as shown, making sure to align them with the curvature of the top of the pylon.
Cut a pair of ½” long lengths of 1/32”piano wire and press them into the front and back of the pylon as shown,
securing them with thin CA glue. These will serve as the rubber band anchors for holding your wing in place.

It is now time to begin building the wing. The wing is built in four separate panels, and the inner panels are different
lengths. Pay close attention to this assembly process. Match the dihedral breaks to the ribs so that the inner dihedral
ribs are angled less than the outer dihedral ribs. Also pay close attention to the fact that there are 6 dihedral ribs.
They can be identified by the extra slot they have at the main spar to accept the plywood joiners.
You may notice that the ribs have large wedges on them. These wedges support the leading and trailing edge to
achieve the correct conformity to the design undercamber. Do not glue the trailing edge to the wedge, as it will be
cut off using a razor blade after assembly. The same is true at the leading edge.
You may find it helpful to sand the leading and trailing edges to an airfoil before assembly. We used a razor plane to
aid in this process.
Shown below is the sequence for laying out the left inner wing panel.
d

The leading edge is now added.
And finally remaining ribs are installed.
Lastly, the spars are added. You will need to flip the panel upside down to add the bottom spar. Note that many of
the spars are keyed to the wing and must be oriented correctly. The top and bottom spars are different to allow for
dihedral.

Next, the right inner panel is assembled in the same manner.
The dihedral mating faces should be sanded for a good match.
The outer panels only use one dihedral gage.

The wingtips use doubled up outer ribs as shown which should be added after the spars are installed. Sand them to
a smooth transition as shown after assembly. This is also a good time to give all of the wing parts a careful sanding.
You can leave the undercamber supports in place for now or cut them out as you sand the wing panels.

Locate the plywood wing joiners and match them to the dihedral breaks. You can glue each joiner to a wing panel
before beginning to jig the panels into place.

Once you have finished joining the wing panels and sanding the dihedral breaks and removing the undercamber
wedges, your wing is complete!

Assemble the stab over the plans as shown. You may wish to sand the leading and trailing edges prior to assembly.
The lower stab spar is added after assembly.
Finally, the stab tips are installed and sanded to match the overall profile.

Take your time sanding the fin to an airfoiled section as shown. It is made from 1/8”balsa to prevent warps, but this
means it is optimal to remove a lot of material as shown. Sanding to this fully streamlined section will both lighten
your model and provide better yaw response. Wait until after covering to attach the fin to the fuselage. We chose
to finish our fin with Minwax spar varnish, however you could also dope tissue onto the fin to seal it.
Assemble the nose block and sand it to match the fuselage. This is also a good time to sand the fuselage so that it
has no rough edges to disturb the covering.

Add the plywood rubber motor reinforcements inside the fuselage as shown.
The stabilizer leading edge is held down using a Shocer style slotted mount. It is assembled from a layer of plywood
and a layer of 1/16”balsa as shown. Attach it to the fuselage as shown.

The structure for your Saturno is now complete. Give the entire structure two coats of nitrate dope in preparation
for covering. We chose to use polyspan to cover the fuselage, which required the use of Sig Stix It to provide a good
heat activated bond. The flying surfaces were covered with 0.6 mil doculam lightly misted with Design Master paint
on the adhesive side. This is a very easy to use covering, however it adds considerable weight, and a better solution
is to use either tissue or ¼ mil mylar. The mylar is the best option since it is extremely light, adds a little more torsional
stiffness than doculam, and it won’t rot like tissue. To attach the mylar, you would need to coat the flying surfaces
with either Sig Stix It or thinned Weldwood.
It is not necessary to cover tissue over the mylar on the flying surfaces as the Saturno is not a particularly fast model,
and adding tissue over the mylar would just add unnecessary weight.
If you choose to cover your model with tissue, you can simply activate the nitrate dope by soaking acetone through
the tissue to bond it to the wood. Once the tissue is applied, water shrink carefully with the flying surfaces pinned
down to avoid warping the structure. Give the finished tissue covering two coats of thinned nitrate dope to fully seal
it.