• Equipped with a water-cooled Isotta Fraschini Asso engine

• Thin-profile radiators installed on the forward sides of the fuselage

• The design closely resembles a surface-cooling (film-circulation) system, optimized to minimize aerodynamic drag

• The radiators are either integrated into the aircraft skin or embedded in such a way that their weight is distributed across the fuselage structure

  🧪 Weight Estimation: Radiator + Oil Tank in the PC7
  Here we re-estimate the internal breakdown of the declared 47 kg, based on design logic similar to that of the Piaggio PC7:

1. Oil Volume (Prioritizing Cooling Performance)
   • For racing use, maximum cooling efficiency is assumed, with approx. 30 liters of oil on board

   • Specific gravity of aviation engine oil: 0.9 kg/L

   • Oil weight: approx. 27–30 kg

2. Oil Tank (Aluminum Construction)
   • Located just beneath the engine, mounted forward

   • Capacity around 30L, built from ultra-thin aluminum (≤1.5mm thick)

   • Weight: approx. 3–4 kg

3. Radiator (Fuselage Side-Mounted)
   • Thin-film structure following the curvature of the fuselage

   • Despite the large surface area, the materials are extremely lightweight (supported by the airframe)

   • Internal piping is ultra-fine, made from brass or aluminum for corrosion resistance and heat dissipation

   • For racing + bonded installation: weight approx. 13–17 kg

     📊 Estimated Breakdown (PC7 Spec)

Component Estimated Weight
Engine Oil (max load) approx. 28–30 kg
Oil Tank (aluminum) approx. 3–4 kg
Radiator (thin side-mounted) approx. 13–15 kg
Total 47 kg
💡 Explanation:
This configuration fits the unique design philosophy of the Piaggio PC7 exceptionally well:

• Primary cooling is handled by thin-profile radiators exposed to direct airflow

• Placing the oil tank close to the engine improves circulation efficiency

• Both the tank and radiator are designed as consumable components integrated into the aircraft’s outer skin, balancing weight reduction with ease of maintenance


🔍 Piaggio PC7 の冷却構造：前方側面ラジエーターの場合

📌 特徴的な設計要素：

• 水冷エンジン（Isotta Fraschini Asso）を搭載
• 機体前方の側面に「薄型ラジエーター」を設置
• 表面冷却型（皮膜循環式）に近く、空気抵抗を最小限に抑えるデザイン
• ラジエーターは機体の外板と一体化しているか、埋め込み式で重量を機体構造に分担させている

🧪 重量推定：PC7のラジエーター＋オイルタンク

ここでは47 kgという公称重量の中から、Piaggio PC7 のような設計思想に沿って、オイル・タンク・ラジエーターの内訳を再推定してみます：

1. オイル量（冷却を優先）

• レース用で冷却性能を最大化するため、約30L程度のオイルを搭載と仮定
• 航空エンジンオイルの比重：0.9 kg/L
• オイル重量：約27～30 kg

2. オイルタンク（アルミ製）

• エンジン直下、前方設置
• 容量30L程度、板厚1.5mm以下の極薄アルミ製
• 重量：約3～4 kg

3. ラジエーター（機体側面に設置）

• 側面に沿う薄膜構造
• 表面積が広くても構造材が非常に軽量（機体が支持）
• 内部配管は極細で、素材は真鍮またはアルミ（耐腐食・放熱重視）
• レース用途＋貼付式＝重量：約13～17 kg

📊 推定内訳（PC7仕様）

It finally was completed.

Memo
* As for the engine, Isotta Fraschini, Asso is special.
It resembles an engine “cantilever” used for Savoia S.65.
* A wing and the front hydrofoil are right and left asymmetry
(these support torque)
* The hull has an opening and shutting-type air in take in the side. (I confirm a window two type and a window three type)
* A clutch sandwiches front and back of the engine (for air propeller use and the water screw)
[important] Pilot needs three arms to change this at the time of a takeoff.
* The exhaust pipe confirms a long type and a short type. I choice long type (an improved model?).
* The biggest mystery. I do not know where is the sensor (Pitot tube) of the air speed instrument in. (is this because it was abandoned before completion?)
* The clutch assumes a spring expression.
* Thanks for cooperation of Mr. Giambattista.

メモ
＊エンジンはイソッタ・フラスキーニ・アッソ改。サヴォイアS.65に使用されたエンジンと同時期に開発された「カンチレバー」に酷似しています。
＊翼は左右非対称
＊前部水中翼は左右非対称
＊開閉式のエアインテークと思われる窓を持つ（窓2つタイプと、窓3つタイプを確認）
＊エンジンの前後をクラッチが挟む（プロペラ用とスクリュー用）
離陸時にこれを切り替えるため、パイロットは腕が三本必要。
＊エクゾーストは長いタイプと短いタイプを確認。今回は長いタイプ(改良型？)を選択。
＊最大の謎。エアスピード計器のセンサー（ピトー管）がどこにつくのか分からない。（完成前に放棄されたからか？）
＊クラッチはスプリング式を想定。
＊Giambattista氏の協力に感謝。

Finally ready for final rendering is now ready. 10000 × 10000-pixel rendering takes about 10 hours. I must wait for the weekend without work.
いよいよ最終レンダリング。1万ピクセル×1万ピクセルのレンダリングに約10時間かかります。
仕事のない週末を待たねばなりません。

I was connecting the pipe to the oil cooler.
The cooling system of the pipe is placed, carburetor was detail up.

Radiator Part

Oil cooler? (Guess)

Top surface appearance

Original radiator photos.
The radiator has a slit. But there is no space at the time of mounting. I guess that part made of different materials that it is oil cooler.

It bulge slightly from the radiator surface.